by

Plai Keng Ya.ng

B. Sc., University of Hong Kong, ' 1965

in the Depqrtnent

Chemistry

This i s t o c e r t i f y t h a t t h e t h e s i s e n t i t l e d

by M r . :I. K. Yang i n p a r t i a l fu i f i l l f i l en t of t h e

requirements f o r t h e dezree of 2,laster of Science

meets t h e s t a n d ~ . r d s of t h e Depr tmen t of Chemistry,

Simon Frasel- Universit ,y.

Chairman P r o f e s s o r EI. G.,,,?~I~K

P r o f e s s o r Y, L . Chow

P r o f e s s o r L. K, Pe te r son

I wish e s p e c i a l l y t o express my

s i n c e r e g r a t i t u t e t o P r o f e s s o r D. G , Tuck

f o r his cont inued i n t e r e s t , gui.dance and

a s s i s t a n c e , Thanks a re due t o my co1leagu.e~

and t h e Sinon F r a s e r Unive r s i ty t e c h n i c a l

s t a f f f o r t h e i r a s s i s t a n c e and h e l p a t

t h e Department of Chemistry. The f i n a n c i a l

a s s i s t a n c e f rom t h e Depr tmen t of Chemis-5ry,

Simon P r a s e r Univer .s i ty and from t h e Nat ional

Research Council of Canada i s g r a t e f u l l y

COIQTZNTS

I. INTRODUCTION ,

11, LITERATURE REVIEW

(A) ~ e n e r a l Chemistry of Indium

(B) Compounds of XndZurn

(c) Coordination Chemistry of Indium

(a) Neutral Complexes of Indium(II1)

(b) Cationic Complexes of Indium(II1)

( c ) Anionic Complexes of Indium(II1)

(D) The Coordination Chemistry of Unsaturzted

Sulphur' Donor Ligands 24

111. EXPSFiIMENTAL METHOES

Physical Measurements 27

Analy t i ca l Techniques . 2 8 -

Prepara t ion of Maleon i t r i l ed i t h i o l a t e and Its

Complex Compounds 36

Prepara t ion of 1 ,l *-dicyano-2,2 ' - d i t h i o l a t e

and Its Complex Coxpounds h-3

Prepara t ion of T o l u e n e - 3 , b d i t h i o l a t e Complex

Compounds 4 5

IV. POLAROGRAPHY

( A ) P r i n c i p l e s , of Method 5.3

( B ) Review of .Polarographic Studies of Indium 55

(C) Experimental 57

(D) Results and Discussion 76

(a) The Study o'f Half-wave Potential and

Reversibility

(b) Stability Constant Studies

( c ) Coordination Number Studies

RESULTS AND DISCUSSlON

(A) Conductivity Results 79

(B) The Infrared Spectra of Indium Dithiolate

Complexes and Their Adducts 89

(C) The I?KR Study of 1 ,lo-Phenanthroline and 3-01

2,2'-3ipyridyl in Indium(I11) Dithiolate Complexes

(D) The UV Spectra of Indium(II1) Dithiolates and

Their Adducts 118

(E) Structural Discussion

VI. SUGGESTIOK FOR FURTHER RESEARCH

BIBLIOGRAVZY

LIST OF ABBREVIATIONS

CHAPTER I

I M T R ' O D U C T I O N

Although t h e genera l chemistry of ind.ium i s well

e s t a b l i s h e d t h e r e has only recen t ly been a d e t a i l e d

i n t e r e s t i n i t s coordina t ion chemistry. Complexes of

4 P 5 indiuir(111) p e r c h l o r a t e 2, h a l i d e s ', pseudo-halides , 6 and n i t r a t e , and ad-ducts of th'ese with n e u t r a l monod-entate

7 o r b i d e n t a t e l i g a n d s have rece ived a t t e n t i o n , The p r e s e ~ t

s t u d i e s have been concerned with an i n v e s t i g a t i o n of cor,plex

formation between indium(II1) and c e r t a i n unsa tura ted

b i d e n t a t e sulphur-donor l i g a n d s such a s ma l -eon i t r i l ed i th io la te

(MNT) , 1,l-dicyanoethylehe-2,2-dithiolate ( ~ M N T ) - , and

t o l u e n e - 3 , b d i t h i o l a t e (TDT), and adducts of t h e s e complexes

with some n e u t r a l and anioni c l igands . Several complexes,

with apparent coordina t ion numbers of f o u r , f i v e , o r s i x

have been prepa-red, and t h e i r composition, chemical , and

physf c a l p r o p e r t i e s i n v e s t i g a t e d ; the ox ida t ion s t a t e s of

indium i n t h e complexes and t h e half-wave p o t e n t i a l s were

found us ing polarographic techniques. Polarography was a l s o

used t o f i n d s t a b i l i t y cons tan t s , e spec ia l ly i n t h e

and [I~(TDT)~- . /

CHAPTER I1

11,. ( A ) GENERAL CHEMISTRY OF I E D I U N ----

Inaium was discovered by Reich and. R i t che r i n 1863

dur ing a s tudy of t h e mineral S p h a t e r i t e , and t h e element

owes i t s name t o t h e prominent indigo b lue l i n e i n i t s

' emisgion spectrum.

Indium (atomic number, 2=49) belongs t o group IIIB

S.n t h e p e r i o d i c t a b l e , and atomic weight i s 114.81; t h e

1 0 2 1 e l e c t r o n i c conf igura t ion of t h e element i s K r 4d 5s 5p

Meta l l i c indium i s usu-ally prepared e i t h e r by reduct ion

of t h e oxide with hydrogen, o r by e lec t ro-depos i t ion . The

phys ica l p r o p e r t i e s of t h e element a r e similar t o cadmium

and t i n , It i s a s i lve ry -whi te , l u s t r o u s meta l ; indium i s

one of t h e s o f t e s t elements and can be e a s i l y c u t with a

k n i f e , Although i t s mel t ing po in t i s comparatively low

(156,4 c), t h e b o i l i n g p o i n t i s high (about 2700 C ) . The

chemistry of indium i s genera l ly similar t o t h a t of t h e

r e l a t e d g o u p I I I R elements aluminiu~v, gall ium and tha l l ium.

Hovever, t h e amphoteric cha rac te r of t h e hydroxide of indium

. is considerably l e s s pronounced than those o f gal l ium and

aluminium, and indium sulphide , In S i n c o n t r a s t t o t h e 2 3'

$

gal l ium and aluminium su lph ide , i s s t a b l e i n t h e presence

of water,

Indium forms compoufids i n t h e 4-1, + 2 , and + 3 formal

ox ida t ion s t a t e s , The t r i v a l e n t s t a t e i s more s t a b l e than

t h e lower valency s t a t e s whose compounds r e a d i l y '

d i sp ropor t iona te i n t o I n ( I 1 I ) compounds and f r e e metal i n

t h e presence of water. I n genera l , however, t h e monovalent

compounds of i n d i m a r e somewhat more s t a b l e than those of

gallium. The ex i s t ence of indium(11) spec ies i s , however,

r a t h e r doubt fu l . Although compounds of t h e c o r r e c t

s to ichiometry have been i s o l a t e d , these a r e d iamagne th ,

and n o t paramagnetic as would be expected f o r indium(I1)

compounds, It has been suggested 8.,9 t h a t these compounds a r e

i n f a c t mixed valence spec ies of indium(1) and indium(ZI1)

and do not involve t r u l y b i v a l e n t indium, Recently,

10 however, evidence has been presented f o r t h e ex i s t ence of

s h o r t - l i v e d 1 n ( I I ) spec ies i n a matrix of f rozen aqueous

s u l p h u r i c a c i d a f t e r i r r a d i a t i v e s of indium(II1) su lpha te

with x - ray r a d i a t i o n a t 77'~. The evidence f o r t h e ex i s t ence

b

of shor t - l ived indium(I1) s p e c i e s w i l l b e f u r t h e r discussed

l a t e r i n t h i s t h e s i s .

11, ( B ) COMPOUNDS OF I N D I U M I N THE TRIVALENT STATE

A very l a r g e number of t h e simple compounds of indium(111)

were prepared and i d e n t i f i e d fol lowing t h e discovery of t h e

element,

A l l f o u r indium(II1) h a l i d e s a r e known, Anhydrous

indium(II1) f l u o r i d e , InF . i s prepared b y hea t ing In 0 i n 3 ' 2 3

-1lZ,-1-2 hydrogen f l u o r i d e , and i s i n v o l a t i l e and. extremely

Inso lub le i n water. Anhydroi~s Indium( IIT) ch lo r ide , InC1 3,

and bronide, InBr3, can be prepared by h e s t i n g i n d i m metal i n

c h l o r i n e o r bromine gas, The iodide can be prepared by

hea t ing s to ich iomet r i c amounts of indium metal and iodine i n

an evacuated sea led tube. These h a l i d e s a r e s u f f i c i e n t l y

v o l a t i l e t o be sublimed under vacuum, Solu t ions of indiu.m(I11)

c h l o r i d e and bronlde a r e prepared d i r e c t l y by d i s so lv ing

indium metal i n hydrochlor ic o r hydrobromic ' ac id , Poss ib le

compl exing pseudohalide ions include cyanide, th iocyanate ,

cyanate , and a z i d e ; honever only indium(II1) cyanide and

th iocyanate have been prepared. Indium(II1) cyanide w a s

r epor ted by Meyer l2 and by Wyrouboff l3 a long t i n e ago.

The compound w a s obta ined by adding an aqueous s o l u t i o n of

potassium cyanide t o an aqueous s o l u t i o n of an indium(111)

s a l t ; it w a s descr ibed as an inso lub le p r e c i p i t a t e , b u t

s d ~ u b l e i n excess of potassium cyanide. However, t h e compound

t

was found t o be uns table i n water producing hydrocyanic a c i d ,

which has c a s t considerab3.e doubts upon these r e p o r t s ,

Recently indium(111) cyanide was r e i n v e s t i g a t e d and prepared

i n s o l i d s t a t e by a number of methods, one being t h e r e a c t i o n

1 3 of indium metal o r indium hydroxide with HCN gas a t 3 5 0 ~ ~ . A t t h e same time t h e p repara t ion of iridium(II1) th iocyznate ,

I~(scN) has been repor ted , There a r e two methods f o r t h e 3

prepara t ion . The f i r s t involved r e a c t i n g one mole of

anhydrous indium(I11) ch lo r ide w i t h t h r e e moles o f sodium

th iocyanate i n e thanol 14, t h e second, t h e r e a c t i o n of

indium (111) su lpha te i n aquebus s o l u t i o n with t h e equiva lent I

q u a n t i t y of barium th iocyanate , followed by a slow r e m ~ v a l

15 of the water i n vacuo . Anhydrous and hydrated indiun(111) n i t r a t e a r e both

known, Anhydrous indium(I1I) n i t r a t e can be prepared by t h e

reactkon of anhydrous indium t r i c h l o r i d e with d in i t rogen

pentoxide 16; t h e hydra te of t h i s compound i s obta ined by

d i s s o l v i n g indium metal i n concentrated n i t r i c a c i d , followed

by evaporat ion and c r y s t a l l i z a t i o n of t h e s o l u t i o n t o g ive

~ n d i u m ( I I I ) sulpW.de, I n S which i s yellow o r b r i c k 2 3'

brown i n colour and very s t a b l e i n water , is p r e c i p i t a t e d when

hydrogen su lphide i s passed i n t o a n aqueous s o l u t i o n containing

a weak a c i d such as a c e t i c a c i d ,

The formal ox ida t ion s t a t e s indiurn(11) and ( I ) have

been s t a b i l l s e d i n compounds such as h a l i d e s , su lphide ,

and oxide, The most important simple compounds of i n d i u m ( I I I ) ,

(11) and ( I ) a r e summarized i n t h e t a b l e 11-1,

I

Table 11-1

Summary of t h e Simple Compounds of Indiun

Oxidation S t a t e Oxidation S t a t e Oxidation State

-111 I1 I

InF 3 c o l o u r l e s s InP2 co lour le s s ..)

co lour les s 1nCl2 co lour le s s InCl lemon yellow

InBr3 co lour le s s InBr2 almost InBr carmine

co lour le s s

In13 yel lowish I n I 2 almo s t I n 1 carmine

co lour le s s

I n 2 0 j yel lowish In20 b lack

In2'3 yellow o r I n s wine r e d In2S brown black

b r i c k r e d

I n (scK) co lour l es s

I ~ ( C N ) ~ co lour l e s s

I ~ - ( N o ~ ) co lour le s s

11, (c) THE COORDINATION CEEKISTRY OF INDIUM (111 ) - I

Studies of t h e coordinat ion chemistry of indium(II1)

have shown t h a t coordina t ion numbers of t h r e e , f o u r , f i v e

and s i x a r e poss ib le , of which s i x appears predominant,

Indium(II1) complex compounds can obviously be c l a s s i f i e d ,

as n e u t r a l , an ion ic o r c a t i o n i c spec ies , a l l of which have

been examined, The phys ica l p r o p e r t i e s s t u d i e d inc lude

e l e c t r o l y t i c a l conductance, i n f r a r e d and Raman s p e c t r a ,

thermogravimetric measurements. X-ray c r y s t a l l o g r a p h i c

s t u d i e s have a l s o been c a r r i e d ou t on a small number of

compounds.

( a ) Neutral Complexes of Indium(I11)

I n - genera l , s i x types of n e u t r a l complexes have been

repor ted , namely : InX3L3, InX3L2. 5, 1nX L I ~ x ~ L ~ . 5, I ~ X + 3 2'

(where X is a h a l i d e o r pseudohalide, and L i s a donor

( l i g a n d ) ) , p l u s c h e l a t e comncunds . The p r o p e r t i e s of t h e s e

n e u t r a l complexes have been examined e i t h e r by i n f r a r e d

spectroscopy, o r by e l e c t r i c a l conduct ivi ty measurements

i n non-aqueous so lven t s such as nitromethane, ni t robenzene

o r a c e t o n i t r i l e ,

InX L r Comglexes 07 InX L where L i s a monodentate 3 2 3 3

l i gand a r e wel l knotm. Since both i n f r a r e d s p e c t r a and

condvctivl t y measurements have suggested a n e u t r a l

spec ies 17'18919 t h e coordina t ion number i s be l i eved t o be

s i x o Indium(111) ch lo r ide complexes a r e known with t h e

l i g a n d s urea , th iourea , pyr id ine , pyridine-N-oxide,

4-cyano-pyridine, and dimethyl su1phoxid.e; indium(I11)

bromide with pyr id ine , u rea , dimethyl sulphoxide, and

indium(II1) iod ide complex with pyr id ine on ly ; and indiurn(1II)

th iocyanate with u rea , th iourea , pyr id ine , tr iphenylphosphine

14 and 4-p icol ine

I n L : Only one compound has been obta ined i n t h i s 3 205

type; indium t r i c h l o r i d e d i s so lves i n N,Nt-dimethyl-acetamide

(dma) t o g ive InCl (dma)2e5. 3 Conductivity measurement

shows t h a t t h e compound i s n e u t r a l , bu t t h e s t r u c t u r e of

t h i s compound i s s t i l l doubt fu l ,

InXgLZt This type of complex where L i s again a

monodentate l i g a n d and X i s a h a l i d e , may be e i t h e r a

f ive-coordina te monomer o r a polymeric s p e c i e s , The

compounds found inc lude TnCl ( ~ h PO) 2 , 3 3 InCl (Ke 3 3

El)

Q)

3 I+ 2' 0

0

0

a

.d rl

cd C

0 a I

0

M a

Ti

2 Q, a

.I4

rl d C

n

H

H

H

V

fi 5

.d a

F; H

.. u\

rl

2 H

Q)

C

cd c, 0

0

E .,-I s

L4 E

l) 0

C a

rl h

C

PI M

rl

P 0 cl

k a

F; H

a

F; cit

0

C

(d

c, 0 0

2 .d s

L4 CJY 0 s

Pi rl h

$ C

01

k 7

0

G-r

Q)

P a

rl

ro s M

El)

Q,

X

a, rl

0

0

Q)

KI Q

, C

c,

G-l 0

k

Q)

P

E 5

F: F: 0

.d

c, 6

C

d

d

k 0

0

0

a,

8

They presumably a r e s i x coordina tes , with pse;do-octahed.ral I

s t r u c t u r e s , A number of o t h e r . che la t ing l igands , such a s

sa l icy la ldehyde and b-d ike tone , t r i f l u o r o a c e t y l a c e t o n e

d e r i v a t i v e s , a l s o form n e u t r a l In(111) c h e l a t e complexes.

(b) Cat ionic Complexes of Indium(I11)

During s t u d i e s of indium(II1) spec ies us ing ah

i o n i c volume measurement technique, Celed-a and Tuck found

evidence f o r t h e ex i s t ence 0.f 0 ) 13' i n d i l u t e 2 6

aqueous pe rch lo re te a c i d s o l u t i o n 24. The s o l i d c r y s t a l

obta ined from t h e corresponding s o l u t i o n is

b n ( ~ ~ 0 ) a ( ~ 1 0 ~ ) 3 . @ ' 2 ~ 2 ~ i n which t h e pe rch lo ra te anion

was shovm t o be non- l iga t ing by i n f r a r e d spec t roscopic

methods, This compound has been used as t h e s t a r t i n g

m a t e r i a l f o r t h e p repara t ion of var ious indium(II1) c a t i o n i c

6 complexes , The fol lowing c a t i o n i c complexes have been

( c ) Anionic Complexes of Indium( 111)

A number of indium(II1) an ion ic compleyes a r e known

with t h e l igands su lpha te 26 25'26, o x a l a t e 27, h a l i d e s , plus

adducts of t h e s e spec ies with n e u t r a l donors 3*6. The

coord.ination number of t h e s e complexes i s f o u r , f i v e , o r s i x ,

with s i x being t h e most common.

There a r e e a r l y r e p o r t s of indium(II1) su lpha te

complexes such as [ E ~ ~ N H ; ] [ I ~ ( s o ~ ) with var ious amounts - +

of water , and t h e o x a l a t e ~~1 .- 1n(c204)J .nH20 where H=BEq

M ~ [ I ~ ( c ~ o ~ ) J could be prepared. It i s be l ieved t h a t a l l t h e s e

compounds involve s i x coordina te indium(II1) .

The a n i o n i c complexes of i'ndiun(111) h a l i d e s were

f i r s t r epor ted by Ekeley and P o t r a t z 26; i n l a t e r works t h e s e

h a l i d e complexes have been formulated as an ion ic complexes

- 2- I ~ X ~ , InX5 , I ~ x ~ ~ - , and InX 4- 8 7 . The an ion ic spec ies

- InXh has been assigned a t e t r a h e d r a l a n i o n i c s t r u c t u r e by

v i b r a t i o n a l s p e c t r a 28p29p30 and t h i s has r ecen t ly been

31 confirmed by x-ray crys ta l lography . Brown, E i n s t e i n and Tuck 32 have s t u d i e d t h e

f i v e coordinate c h l o r i d e compound, (Et4N)21nC1 by x-ray 5

c rys ta l lography ; t h e anion InCl 2- has a t e t r agona l , 5 .

pyramidal s t r u c t u r e as shown i n Figure 11-1. Five coordinate

anionic complexes have been found t o be important in the work

described in t h i s thesis.

I n r e cen t years , many paper have been publishe6. on

t h e c o o r d i n a t i o n behav io r of unsatu-ratecl b i d e n t a t e s u l p h u r

donor l i p n d s six3 2s (I11 j , (Pi) and (V) .

/s- 's-

The f i r s t r e p o r t ipp6ars t o be t h a t of Schrauzer and

Mayweg 33 who obta ined t h e n e u t r a l complex ( V I ) by t h e

r e a c t i o n of n icke l su lph ide 'with diphenylacetylene, o r

by t h e r e a c t i o n of n i c k e l carbonyl, su lphur , and

diphenylacetylene.

A t t h e same time, H.B. Gray e t a l . 349 359 36 repor ted a

number of m a l e o n i t r i l e d i t h i o l a t e (MNT) complexes with t h e

2+ 2+ d i v a l e n t metal ions N i , cu2+, zn2+, and Co , as i n ( V I I )

Obviously, t h e comparison o f t h e ox ida t ion s t a t e s i n

( V I ) and ( V I I ) r e v e a l s a d i f f e r e w e of two e l e c t r o n s ,

a s s o c i a t e d e i t h e r with t h e c e n t r a l metal o r on t h e c h e l a t e

rings, depending apparent ly on t h e s u b s t i t u e n t s ( c N o r

C H groups) . The compounds ( V I ) and ( V I I ) a r e q u i t e s t a b l e , 6 5

which r a i s e s t h e p o s s i b i l i t y t h a t ( V I ) spec ies might be

r educ ib le t o mono o r d-inegative anions , wherea-s t h e ( V I I )

spec ies might be ox id izab le t o a monoanion o r n e u t r a l complex,

L a t e r , Dav$son e t al. 3 7 9 3 8 synthes ized complexes of t h e type

( V I I I ) i n d i f f e r e n t ox ida t ion s t a t e s , and s tud ied t h e s e

polarographi c a l l y and spec t roscop ica l ly .

The polarographic study of t h e complexes ( V I I I ) h m given ,

information on t h e ox ida t ion s t a t e s ,. ha l f -wave p o t e n t i a l s 6

and s t a b i l i t i e s of such square p lana r conplexes 'O ( s e e

t a b l e 11-3).

Table 11-3

R a l f -wave P o t e n t i a l s of P lanar --- Conp'l exes i n Non-Aaueous

So lu t ion

.I

Couples Sol vent

CH3CN + O . O j O ( a )

bH3CN

CH3CN

CH CN 3 CH3CN

DMF

DMF

DMF

DMF

DMF

+0,210 ( a )

+0.226 ( a )

+0.330 (a)

i-0.440 ( a )

-1.46 (b)

-1 e41 ( B )

-1,068 ( b )

, -1.145 (b)

-1.95 (b)

( a ) Measured a t room temperature r e l a t i v e t o an aqueous

calomel e l ec t rode s a t u r a t e d with NaC1; r o t a t i n p l a t i n m

39 i n d i c a t o r e l ec t rode ,

(b) Measured a t room temperature r e l a t i v e , t o a Ag/AgC104

. e l ec t rode ; dropping mercury e lec t rode ( H,S. Gray e t al.

unpublished work 40 )

- -- --

- 20-

A number o f cnmnents can be made about t h e s e r e s u l t s . F i r s t l y ,

I

f o r complexes f o r a s i v e n l i g a n d wl th meta l s i n t h e same

o x i d a t i o n s t a t e , t h e o r d e r of half-wave p o t e n t i a l s q i v e s

t h e o r d e r of s t a S i l i t y of t h e comnlexcs. This s t a b i l - i t y

ord-er i s Cu>NisCo i n t h e diani0ni .c .PTJT~- s e r i e s , and

2- Ni)Cu>Co>Fe i n t h e d i a n i o n i c TDT s e r i e s . Proceeding

down t h e p e r i o d i c ta.ble i n t h e n i c k e l group, t h e s t a b i l i t y

2- o r d e r i s ICi < ~ d < ~ t i n bo th t h e 1 ~ 3 ' ~ ~ - and TD'P s e r i e s .

Secondly, t h e h a l f -wave po ten t1 a 1 i n d i c a t e s t h e ea se o f

e l e c t r o n I t ransf e s and hence t h e e a s e of forrnin.5 d i f f e r e n t

o x i d a t i o n s t a t e s i n s o l u t i o n . From t h i s in format ion , i t

i s possibl 'e t o s e l e c t reduc ing a g e n t s f o r sy f i t he t i c work

on thes,e complexes.

However, t h e problem o f meaningfully a s s i g n i n g t h e

o x i d a t i o n s t a t e s of t h e c e n t r a l me ta l s in t h e s e c o r r ~ l e x e s

i s s t i l l a very s u b t l e one , 41

7 The c r y s t a l s t n l c t u r e of t h e cornpounds ~ C H ~ ) ~ I I ~ [ N ~ ( F ~ R T ) 3

shown t h e e x i s t e n c e of s t a b l e squa re p l a n a r s t r u c t u r e s , with

t h e metal atom i n t h e same p lane as t h e su lphur a t o ~ s . Bond

l e n g t h s an+ a n e l e s have a l s o beea measured by x -my ge thods

t h e ca t ions occupy p o s i t i o n s above and below t h e p l ane .

U n t i l t h e r e c e n t s t u d i e s , t h e square p lanar geometry w a s

8 : be l i eved t o be. r e s t r i c t e d t o t h e diamagnetic, d complexes

except f o r a few paramagnetic (S = $ ) , square-planar Co(I1)

and Cu(I1) complexes.

Complexes of coordinat ion number s i x with unsa tura ted

b i d e n t a t c sulphur-donor l igands of the genera l s t r u c t u r e

42 ( I X ) and (x ) h a v e b e e n repor ted . - I . .

M=V, C r , Mo, W , Re, Fe,

R*,. Os, and c;.

I n f a c t , t h e f i r s t of t h e l igands mentioned i n (VIII) I

introduced was t o ' l u e n e - 3 , b d i t h i o l a t e (TDT) ( X ) , o r i g i n a l l y

used by Clark i n 1936 f o r t h e co lo r ime t r i c deterrninatjon

of t i n 43'44. Since t h a t t ime, TDT has been used as a

q u a l i t a t i v e t e s t f o r such metals as No, W , and Re, bu t t h e r e

had been no f u r t h e r study of t h e complex compounds u n t i l

r e c e n t l y , The f i r s t a c t u a l i s o l a t i o n of a complex of t h i s

s t o i c h i o n e t r y w a s by G i l b e r t and Sandel l who made Mo(TDT) 45 3 '

The s ix-coordina te complexes a r e extremely i n t e r e s t i n g ,

because x-ray c r y s t a l l o g r a p h i c and spec t roscopic measure-

ments s t rong ly i n d i c a t e t h a t (VII) and ( V I I I ) have p e r f e c t ,

o r nea r ly p e r f e c t , t r i g o n a l p r i smat i c 'coordination i n s t e a d

of t h e more usual pseudo oc tahedra l s t r u c t u r e 46,47,48

X-ray s t r u c t u r a l i n v e s t i g a t i o n of t h e 6-coordinate

R ~ ( s ~ c ~ P ~ ~ ) ~ complex has shown t h a t rhenium i s surrounded

by t h e s i x sulphur atoms i n a near ly p e r f e c t t r i g o n a l -

p r i smat i c coordinat ion. The s i d e s of t h e prism are square ,

A perspec t ive drawing of t h e coordinat ion geometry i s shown

i n Figure 11-2,

Fig. 11-2 Coord ina t ion in the Re(S2C2Ph2)3con?lex.

The pola-rographic behavior of t h e t r i p o n a l - ~ r i s m t i c

complexes as i n t h e RNT and TDT s e r i e s shows t h a t a s e r i e s

of r e v e r s i b l e one e l e c t r o n t r a n s f e r s . occur:

These r e s u l - t s i n d i c a t e a t l e a s t t h e t r a n s i e n t

ex i s t ence of reduced o r oxidized spec ies which probably

a l s o possess the t r igona l -p r i smat i c geometry. Unt i l

very r e c e n t l y , l i t t l e informationb6 w a s , a v a i l a b l e about

t h e s t r u c t u r e s of n e u t r a l and monoanionic spec ies

( v s ~ c $ ~ ~ ) and (vs6c6~h6)!- which a r e a l s o probably

t r igona l -p r i smat i c . However, a r e c e n t s t r u c t u r e of

keblg [ V S ~ C ~ (CW) 63 has revealedb7 t h a t t h i s d ianion

adopts a geometry i n t e r m e d i ~ t e between t h e t r i g o n a l l y

d i s t o r t e d ' oc tahedra l and t r igona l -p r i smat i c a r r a n - j e ~ e n t s .

Cer ta in of t h e reduced forms have alrea-dy been i s o l a t e d

w i t h liga,nds IVTT and TDT, 49,50,51,52

CI-~APTER 111 \

1 x 1 . ( A ) PHYSICAL WEASUREWEKTS ---

( a ) I n f r a r e d Spect ra

I n f r a r e d s ,pec t ra were measured with Unicam SP200,

Perkin-Elmer 475 and Beckrnm IR-12 spectrophotometers , with

ranges of 5000-650, 4000-300, and 400-200 an-', r e spec t ive ly .

Spect ra were obtained w i t h Nujol mulls us ing sodium chl-oride

and/or cesium iodide windows, o r potassium bromide p e l l e t s .

( b ) U l t r a v i o l e t Spectra

U l t r a v i o l e t s p e c t r a were taken on a Unicam SP800

Spectrophotometer with a range of 200 .mp - 450 my, genera l ly

us ing a 1 cm. quar tz c e l l , Spectro-qual i ty a c e t o n i t r i l e and

methonol were used as so lven t s .

( c ) Melting Poin t - Weasurements

Kel t ing poin t measurements were c a r r i e d ou t us ing

Fisher-John o r Gallentiamp melt ing poin t apparatus .

( d ) Conductivity Measurements

Conductivity measurements were c a r r i e d out with 10-~1i

s o l u t i o n s i n a c e t o n i t r i l e a t room temperature, us ing

conduct iv i ty meter type C . D . I . $d (Radiometer Ltd. *

Copenhagen). A commercial platinum black e l e c t r o d e was

used; t h e c e l l constant was 0.1 The so lven t , a c e t o n i t r i l e

(F i she r Cert i f ied. g r a d e ) , w a s p u r i f i e d by shaking with a

cold s a t u r a t e d aqueous s o l u t i o n of potassium hydroxide,

fo1lowe.d by prel iminary drying over anhydrous sodium

carbonate and f i n a l l y two d i s t i l l a t i o n s a t 81.0 +_ .0.5 from

53 phosphorus pentoxide

( e ) Nuclear Magnetic Resonance Spectra (NMR)

Nuclear magnetic resonance s p e c t r a were taken on a

Varian A-56/60 Spectrophotometer; t h e coupling constant

( J ) i s given i n cps, and t h e resonance f requencies a s va lues

based on t e t r amethy l s i l ane as t h e i n t e r n a l s tandard . The

so lven t used was dimethyl sulphoxide- d6 ( p u r i t y 99.5%) o r

dimethyl sulphoxide.

( f ) Microanalyses

Microanalyses were done by Alfred Bernhardt, Kax

Planck I n s t i t u t f u r Kohlenforschung, Mulhein ( ~ u h r ) ,

West Germany.

(8) Chemicals and S ~ l v e n t s

Chemicals and s o l v e n t s were of reagent grade and were

used without p u r i f i c a t i o n un less otherwise s p e c i f i e d ,

111. ( B ) AKALYTICAL TECHNIQUES

Indium w a s determined e i t h e r by a gravimetr ic method,

weighing I n 0 o r by volumetric t i t r a t i o n with 2 3'

ethylenediamine-tetra-acetic-acid (E.D.T.A.) using

pyridine-2-azo-4-resorcinol as an i n d i c z t o r . 54955.

The genera l prodedure of t h e gravimetr ic method was t o

w'eigh dupl. icate amounts of a complex i n t o a porce la in

c r u c i b l e ; t h e compounds were decomposed with conc. n i t r i c

a c i d , and d r i e d on a steam-bath, and t h e temperature

graduall-y increased u n t i l v o l a t i l e mat ter was expel led.

The c r u c i b l e s were i g n i t e d a t '1100C i n a muffle fu rnace

and. t h e non-hygroscopic In 0 weighed i n t h e open cru.cible. 2 3

The genera l procedure i n t h e volumetric work v:as t o

weigh ou t d u p l i c a t e q u a n t i t i e s i n t o 150 m l f l a s k s , a f t e r

which t h e compounds were decomposed with conc, n i t r i c a c i d

f o r two hours on a steam-bath; t h e s o l u t i o n was then d i l u t e d

and made s l i g h t l y a l k a l i n e with 3 N arnmoniun hydroxide, as

i n d i c a t e d by t h e p r e c i p i t a t i o n of white indium(111) hydroxide.

The contents were warmed and t h e p r e c i p i t a t e d i s so lved by . . adding sodium potassium t a r t r a t e , Excess ammonium hydroxide

w a s bo i l ed o f f and the.pH of t h e s o l u t i o n ad jus ted t o 8-10

by adding 0.01M s o l u t i o n of borax. F i n a l l y t h e s o l u t i o n 4

w a s t i t r a t e d ' a t 8 0 " ~ (hea t ing i s necessary t o a c c e l e r a t e t h e

r e a c t i o n ) a g a i n s t a s tandard 0w01M s o l u t i o n of EwD*T.A*,

us ing twc drops of i n d i c a t o r , (Concentrat ion of t h e i n d i c a t o r

= 0 ~ 1 % ) ~ The end p o i n t i s i n d i c a t e d by a colour change

from orange-red t o yellow. I I

111, ( c ) PREPARATION OF MALE;ONITRILEDITHIOLATE COWPLEX

COMPOUNDS

(a) Prepara t ion of Sodium M a l e o n i t r i l e d i t h i o l a t e , N a IJIJT- z I I

NaS-C-CN was prepared according t o t h e method of Eahr II

NaS-C-CN

and S c h l e i t z e r . 56 4.9 g of anhydrous sodium cyanide powder *

w a s p a r t i a l l y d isso lved i n 30 m l of N,N -dimethyl formamide

and 7.8 g of CS2 added dropwise with s t i r r i n g f o r 30 minutes.

The s o l u t i o n was then d i l u t e d t o 100 m l wi th iso-BuOE, and

grad-ually warmed, a f t e r which t h e hot s o l u t i o n w a s f i l t e r e d

t o remove unreacted N a C N o The f i l t r a t e was cooled, and.

t h e red-brovm pr i smat i c c r y s t a l s of NaC2NS2* 3Me2NCH0 which

separa ted were washed twice with a small amount of CC14

b i e l d = 20-23 g). The c r y s t a l s were allowed t o s t and f o r

f i v e t o s i x days under 100 m l C H C l dur ing which time a 3' yellow s o l i d p r e c i p i t a t e d ; t h i s w a s washed with C H C l and

3 Et20, and dissolveci i n t h e minimun amount of b o i l i n g EIeOY

i n a Soxhlet e x t r a c t i o n appara tus , The concentrated

s o l u t i o n w a s cooled t o -20 C and e t h e r was added. The lemon

yellow cis-NaZKNT w a s precipitated.. T h i s hydroscopic

sa l t w a s dried and s t o r e d over calcium c h l o r i d e i n a

vacuum d e s s i c a t o r p r i o r t o use.

Table 111-1. The 1.R. Spectra of Na,MNT

Adams and Cornell 57 Present Work

The mate r i a l ob ta ined had an I . R . s p e c t r a i n good

agreement with those i n t h e l i t e r a t u r e . (See Table 111-1).

(b) Indiun t r i c h l o r i d e t r i h y d r a t e . -

InCl e3H20 w a s prepared by d i s so lv ing 5.0 g of indium 3 metal (F i she r s tandard 99.9% pure ) i n concentrated

hydrochlor ic a c i d , followed by removal of excess H C 1 and

H20 on steam-bath. Af ter being d r i e d a t 11-0 C i n an oven

overn igh t , approximately 11.45 g of InCl *3A20 was 3 obtained.

( c ) ( c ~ H ~ ) ~ N ~ ~ ( # N T ) J i tetraethylammonium - bis(maleonitri1edithiolate) i n d a t e ( L I I ) ,

A s o l u t i o n of 6.7 g of N a 2 K N T i n 20 m l of 1 : 2 aqueous

methanol s o l t u i o n w a s warmed on a steam-bath, t h e temperat-ne

of t h e s o l u t i o n being about 65-70•‹c. A s o l u t i o n of 4 .5 g

of InCl * 3H 0 i n 20 m l of 182 aqueous methanol w a s add.ed 3 2

t o t h e w a r m Ka2MNT s o l u t i o n with s t i r r i n g . The colour

of t h e s o l u t i o n changed as t h e 1n3+ was added; t h e s o l u t i o n

w a s then f i l t e r e d and t o t h e f i l t r a t e was added 20 m l of

4 g of ( C H ) MBr i n aqueous methanol s o l u t i o n . Af te r 2 5 4

cool ing i n an i c e ba th , yellow c r y s t a l s formed, and were

separa ted on a Buchner funnel . The yellow c r y s t a l s were

very so lub le i n acetone, so t h a t sodium ch lo r ide and

bromide were e a s i l y removed. Water was added t o the

ace tone s o l u t i o n , f o r r e c r y s t a l l i z a t i o n of ( C H ) N ~ ~ ( M N T ) J 2 5 4

which was d r i e d a t 60-65:~ i n vacuo f o r about . four hours ;

y i e l d 2.8 g of yellow needle c r y s t a l s .

M.P. = 238 - 240

Analy t ica l d a t a :

. 7 C . H N In

C a l c . 36.52 3.80 13.32 21.90

Found 36.61 3.95 . 13.40 21.81

(d ) Prepara t ion of D E ~ ~ N ~ ~ ~ ( H N T ) ') : t e t r a e t h y l - -- 3-

ammonium tris(maleonitriledithio1ate) ----------- i n d a t e ( I I 1 ) .

2.3 g of 1n3+ i n 20 m l of aquequs methanol s o l u t i o n

w a s added t o a w a r m s o l u t i o n of 5.8 g of Na2MNT i n 20 m l

of 1:l aqueous methanol a t GOOC with s t i r r i n g during about

20 minutes (approximate 1n:MNT ( mole r a t i o ) = 1:3.5)

The s o l u t i o n was f i l t e r e d . A s o l u t i o n of 5.6 g of ( E t ) 4 ~ ~ r

i n 15 m l 1:l aqueous methanol s o l u t i o n was added t o t h e

f i l t r a t e a t 60•‹c. Af ter cool ing , f i n e yellow c r y s t c l s

were produced, and these were r e c r y s t a l l i z e d from ho t

acetone/water s o l u t i o n (1 : 2 ) ; t h e lemon yellow needle

c r y s t a l s were separa ted , washed with e the r and d r i e d i n

vacuo a t 60-65Oc about f o u r hours,

M.P. = 168 - 170

Analy t ica l d a t a :

Calc, 46.75 6,54 13.01 12,75

Found 46,87 6,66 13.06 12s77

(e Preparation of etqN [ ~ n ( l @ ? ~ ) 2*o-phed : tetraethyl-

ammonium bis (maleonitriledi thio1ate)l ,lo-phenanthroline

A solution of 0.5 g of 1,lO-phenanthroline (Fisher

Certified Reagent) in 15 ml methanol was ad.ded dropwise to

a solution of 1.5 g Et4N ~ ~ ( N N T ) J in 25 ml methanol at /

50% with stirring. As the 1.10-phenanthroline was

added, the colour of the solution d.istinctly changed from

brownish-yellow to yellow, and after a few minutes fine

lemon-yellow crystals were obtained. These were

recrystallized from hot methanol-acetone solution, and dried

+ -'b at 60-65 C in vacuo for a.bout four hours; yield 1,lg o?

lemon yellow lustrous plate-like crystals.

Analytical data:

C H N In

Calc. 47.66 4.01 13.88 16.26

Found 47.93 3089 13.82 16.26

I (f ) Preparation of Et4N k n ( ~ ~ ~ ) ~ * b i ~ ~ j : tetraethyl- - -----

ammonium bi~(rnaleonitriledithiolate)2,2~-bi~yridyl

The method of preparation was carried out as above,

using Fisher Certified Reagent 2,2'-bipyridyl, The shape

of the lustrous lemon-yellow crys$als was needle-like.

- 3G -

Map, ~ 2 4 1 - 243

Analy t ica l data: ,

C H N In

Calc. 45.81 4.14 14.38 16.88

Found 46.03 3.93 14.44 17.03

45.99 4.11 14.23

(g) Prepara t ion of Et4N [ ~ n ( ~ h l ~ ) ~ e n ) : t c t r a e t h y l

ammonium b i s (ma leon i t r i l ed i t h i o l a t e ) e thylenedianine

, A s o l u t i o n of 0.13 g of ethylenediamine (F i she r

C e r t i f i e d Reagent) i n 20 m l ethanol was newtra l ized us ing

a c e t i c a c i d t o pH = 7-8 and then added dropwise w i t h

s t i r r i n g t o a s o l u t i o n of 1.00 g E ~ ~ N [ I ~ ( M J S T ) ~ ] i n '

40 m l methanol a t 55'~. After a few minutes, small

yel lowish c r y s t a l s appeared and were r e c r y s t a l l i z e d from

acetone-ethanol s o l u t i o n and then d r i e d a t 60' C i n vzcuo

f o r about f o u r hours, The f i n a l product was brownish-

yellow.

MOP, = 181 - 184

Analy t ica l data;

C H . N In

Cal c . 36a95 4.78 16.75 19.62

Found 37.02 4,87 16.78 19.42

(h) Preparation of '(E~~N)~[I~(MNT)~: oxine hydroxy- 7

winoline] : tetrae-t~plammonium 8-hy_droxyuuinolate ---

bis (maleonitriledithiolate) --.- ---- indate (111). - A solution of 2 g of E~~[I~(PNT)~] in 50 ml methanol

was neutralized with tetraethylammonium hydroxide (10% in

water: Eastman Organic Chemicals) and a solution of 0.6 g

of 8-hydroxyquinoline in 15 ml acetone added dropwise to

the neutralized solution with stirring at a temperature

of about 4 ~ O . c ~ The pH of the solu.tion was a.djusted to

6-7 using tetraethylammonium hydroxide before addition of

8-hydroxyquinoline; 25 ml water was then added to the

solution. After overnight standing, a yellow compound

precipitated, and was dried at room temperature in vacuo

for about 'six hours,

Analytical data 1

Cal c , 14.40

Found 14.30

(i ) Preparation of EtkN ~ ~ ( M R T ) 2(dma) & tetraethyl- armnonium bis (maleonitriledithiolate) bis (dimethy1acetanid.e)

indate(111).

2.00 g of E~~N[I~(MBT)JW~S dissolved in excess

N,R9-dimethylacetamide (dma: Fisher Certified Reagent),

and t h e s o l u t i o n hea ted t o 55O and s t i r r e d f o r about one

hour. The s o l u t i o n w a s then kept f o r one o r two days a t

room temperzture, during which time yel lowish rec tangu la r

c r y s t a l s appeared; t h e s e were a i r d r i e d a t room tem?erature

f o r about two hours , The compound decomposed under vacuo.

M.Pm = c?ecoraposed a t 60' , t h e compound tu rn ing yellow.

Analy t ica l da ta r

C H N I n

Calc. 40.20 5.44 13.99 16.40

Found 40.09 5.52 13.35 16.15

L

The compound has lower carbon, n i t rogen , and indium and

higher hydrogen contents than t h e theore t ica l . va lues ,

which i n d i c a t e s t h a t i t might contain moisture. These

r e s u l t s may a l s o be i n d i c a t i v e of t h e low s t a b i l i t y of

t h e compound,

111, (D) PHEiPARATION OF THE LIGAND 1,l'-DICYANOETHYLENE-

2.2. ' -DITHIOLATE. AND ITS CONPLEX CONPOUNDS

( a ) Prepara t ion of Sodium 1,11-diganoethylene-2,Zt-

d i t h i o l a t e (LMNT) . NC'

4Na was preparaed according t o t h e published

method. 58m 4 g of s o d i ~ m metal was d isso lved i n 50 m l of

methanol and t h e solu. t ion made up t o 52.5 m l t o g ive a

s o l u t i o n o f sodium methoxide. To 30 m l NaOMe s o l u t i o n a t

10 w a s added 6.6 g of xhalononitri le: a f t e r cool ing t o 5'

i n an i c e ba th , 3 m l carbon d isu lphide w a s added dropwise

with s t i r r i n g , followed by 15 m l NaOMe and 0.75 ml CS2,

w a s f i n a l l y added, t h e r e a c t i o n mixture kept below 10 b~

i n an i c e ba th y i e l d i n g a yellow p r e c i p i t a t e . The p a l e

yellow sod-lum sa l t obta-ined was used without f u r t h e r

pur5 f i ca t ion . Tne I.R. and U.V. s p e c t r a ( Table 111-2,

111.3) were taken t o confirm t h a t t h e ma te r i a l prepared

was i d e n t i c a l with t h a t d e s c ~ i b e d i n t h e l i t e r a t u - r e .

Table 111-2. Inrared spectra of N ~ ~ ( ~ N N T ) -

Published data (cm -1) 52.59 This work (cmol)

3500 3490

(a) Infrared spectrum was measured with a Psrkin-Elmer

model 42 spectrophotometer using KBr d.isk,

(b) Infrared spectrum was measured with a Perkin-Elner

model 475 grating infrared spectrophotometer using

K B r disk technique,

T a b l e 111-3. U l t r a v i o l e t Spect ra of Nap ( ~ N T )

( a ) (b -1.) Published d a t a ( ,,cm This work ( cm-l)

(a) Elec t ron ic spectrum w a s measured on a Cary Model 1 4

recording spectrophotometer i n a c e t o n i t r i l e s o l u t i o n , .

(b ) U.V. spectrum w a s measured on a Unlcam SP 800

recording s2ectrophotometer i n a c e t o n i t r i l e .

( b ) Prepara t ion of ~ ( " - C ~ H ~ ) ~ % [[n((lMN~) 2 ~ ] :

tetrabutylammonium -- halo b i s (1,l-dicyanoethylene-2,Z'-

d i t h i o l a t e ) indate(111).

A s o l u t i o n of 1.6 g of In(111) (as InCl *3H20) i n 3 1 6 m l of methanol was added dropwise with s t i r r i n g t o a

solv.tion of 6 g of IVa,2(LIGKT) i n 30 m l of methanol. t h e

p~ a f t e r a d d i t i o n of In(111) s o l u t i o n was approximately 4.

The p a l e yellow s o l u t i o n w a s f i l t e r e d and sod-ium chl-oride

e a s i l y removed. The f i l t r a t e w a s added t o a s t i r r e d

s o l u t i o n conta-ining an equimolar quan t i ty of (n-C H ) KX 4 9 4 ( X = C l , B r o r I ) a t 45-50' . After a few minutes, sodium

h a l i d e prec ip i ta , ted and was f i l t e r e d o f f . The f i l t r a t e

was kept overnight a t room temperature, and t h e pa le

yellow c r y s t a l s wh; ch formed were c o l l e c t e d and washed

with water and water-methanol s o l u t i o n (1 :1) and

r e c r y s t a l l i z e d from methanol, y i e l d i n g t r i c l i n i c c r y s t a l s - of (n-CqH9)qN [ I ~ ( ~ N T ) ~ x ~ which were then d r i e d i n

vacuo a t 50 f o r about f o u r hours,

M.P. ( X = C ~ ) = 164-165

(X=Br) = 136-138

Analy t ica l d a t a :

Calc. 50.04 7.55 8.75 8.32 11 95

Found 50.59 7056. 8.78 8,42 l l . 9 8

1

In the chloride and iodide compounds, the indium

percentages were

X = C1

Cal c . 12.52

Found 12.44, 12.48

Calc. 11.41

Found 11.,52, 11.69

(c) Preparation of L ( ~ - c ~ H ~ ) ~ N ] ~ PINT) 4: tetra- butylammonium tris (1 ,l '-dicyanoethylene-2,2'-dithiolate) -- ---

1.6 g of In(II1) (as InCl @3H20) in 23 ml of methanol 3 was added to a stirred solution of 9 g of Na2(LENT) in

30 ml of methanol at temperature of 50 (molar ratio 1n(III):

Na2(iMNT) - = lr3). The yellow solution was filtered and

sodium chloride removed. A solution of 10 g of Bu4NBr

in 20 ml of methanol was added to the filtrate with stirring

at 1+ ' j0 , when a white precipitate of NaBr appeared and was

filtered off. Yellow crystals of the complex were

obtained after stand.ing overnight. Recrystallization

from h.ot methanol-acetone solution gave yellow hexagonal -

crystals, which were washed with water and water-methanol

and dried in vacuo at 500 .

M.P. = 165 - 166 1

Analytical data:

Ca.1 c . 57.07 8.62 9.98 9.09

Found 57 29 8.41 9-83 9.06

(d) Preparation of (pBu4N) [I~(AKNT)~~~~E] : : -- .. .

tetrabutylammonium .- bis<l ,l ' = ~ ~ g a ~ n o - 2 , 2 ' - d i t h i o l a t e )

A solution of 0.5 g of 1 ,lo-phenanthroline in 15 ml

of methanol was added dropwise to a solution of 2.4 g of

("-BuqN) In(&lYNT) 2 B r in 50 ml of methanol at 4.5 '~ wi th

stirring; after a few minutes a yellowish precipitate was

obtained. Recrystallization from a methanol-acetone

solution (1 :1) gave yellowish orthorhombic crystals,

which were filtered, washed with cold water:methanol- ( 1 : 2 )

and dried in va.cuo at 60-65'.

M a p a = 274-276

Analytical. data:

C H N In

Cal c . 52.61 5.88 11 93 13.99

I

- ( e j Prepara t ion o f n - ~ u 4 ~ b n ( i ~ ~ ) - 2 b i p d : t e t r a -

-.

butylammoni~~m -- b i s (1 ,l '-di~yanoethylene-2,2~-d5 t h i n l a t e ) - .---

2,2 ' -bipyridxl ------ indate(111) .

The p repara t ion of t h e compound w a s c a r r i e d o u t as

above. The c r y s t a l s were or thorhonbic , l i k e those of

1 , lo-phenanthrol ine compound.

l'4.P. = 2&1 - 243

Percentage IP: Calc. 14.60 Found 14.44.

111, (E) PREPARATION - OF TOLUENE-3,4-DITHIOLATE COii?LEX

COMPOUNDS

( a ) The l i g a n d , t o l u e n e - 3 , b d i t h i o l (TDT), w a s

procured from Matheson, Coleman and Bel-1 Co. (Tjelting

p o i n t 28-30 ).

(b) Prepara t ion of Et4N [ln ( T D T ) ~ ] : t e t r a e t h y l -

ammonium b i s (toluene-3,b-dithiolate) ------ i n d a t e ( I I 1 ) .

T o l u e n e - 3 , b d i t h i o l (TDT) i n 50 ml- of e thznol w a s

added dropwise t o a s o l u t i o n of 4.3 g of InCl *3H2@ i n 3 200 m l o f e thanol a t 55-60•‹. The s o l u t i o n w a s s t i r r e d

and n e u t r a l i z e d with 3% NaOH i n ethanol t o a d j u s t t h e pH

t o about 3-4. The whi te p r e c i p i t a t e of sodium c h l o r i d e

w a s f i l t e r e d of f and 3.5 g of ( c ~ H ~ ) ~ N B ~ i n 15 m l of

e thanol added t o t h e f i l t r a t e . Af ter cool ing , t h e p a l e

yellow c r y s t a l s were f i l t e r e d o f f a,nd washed with d i s t i l l e d

water until no bromide ion could be identified in the ,

washings, The product was recrystallized from hot ethanol

and dried in vacuo at 60•‹.

M. P. = 205-207

analytical data:

Calc. 47.74 5 . 85 23.15 20 75

Found. 47 . 74 6.14 23.86 ~ 1 . 9 2

( c ) Preparation of ~t,~r~n(~~~),phen]: tetraethyl- +- 4..

ammonium bis ( to luene-3 ,4-di th io l -a te) -l,l0-phenanthrol-ine

indate,(III) . To a solution of 1.58 of Et4N[~n(~~~)2] in 60131 of

acetonitrile, or tetrahydrofuran (THF) was added C.37g. of

1,lO-phenanthroline in 15ml of ethanol with stirring at

temperature of lkO". The colour of the solution changed

distinctly from pale yellow to orange during the addition

of 1,lO-phenantk.,roline. After a few minutes standing at room

temperature, both orange and yellow crystals precipitated

and were subsequently recrystallized from hot acetonitrile-

methanol (2:l) or tetrahyrofuran-aethanol solutions. The

crystals were separated by picking out the yellow precipite

in methanol; the crystals were dried at 60' for about four

hours,

M. P. = 218-220•‹ (orange)

= 276-278•‹ (yelloy)

A n a l y t i c a l d a t a (orange c r y s t a l s ) *

C H S

Calc. 55.65 5.50 1 7 1,5

Found. 55.65' 5.55 17.33

( d ) Pr-eparatiop- -of E t4N ~ ~ ( T D T ) 2dipy] : t e t r a e t h y l -

ammonium bis(toluen6-3,~-dithiolate)-2,2-dip~~rFd~~le i n d a t e ( I I 1 ) .

. The p r e p a r a t i v e method tras e x a c t l y l i k e t h z t f o r t h e

phenan th ro l ine complex, and y i e l d e d orange c r y s t a l s nixed

w i t h ve ry small amount of yel low m a t e r i a l . It w a s n o t p o s s i b l e i

t o o b t a i n a pure sample of t h i s l a t t e r su.bstance.

E1.P. = 158-159

A n a l y t i c a l d a t a :

C B N I n

Calc . 54.19 5.64 5.92 16.18

Found . 54-14 5.61 5.95 16.21

I

CHAPTER IV

POLAROGRAPHY

IV. ( A ) PRINC1PLE.S OF METHOD -- Polarography involves t h e e l e c t r o l y s i s of a s o l u t i o n

of e l ec t ro -ox id izab le o r e l ec t ro - reduc ib le m a t e r i a l s

between a dropping mercury e lec t rode and some re fe rence

e lec t rode . The p o t e n t i a l a p p l i e d between these i s varied

and t h e consequent change i n t h e flow of cu r ren t a r e

measured. The dropping mercury e lec t rode (DME) i s

experimentally s imple, c o n s i s t i n g of a f i n e c a p i l l a r y

a t t ached t o a r e s e r v o i r conta in ing mercury, which passes

slowly down t h e c a p i l l a r y and emerges i n t h e form of small

drops. The comnonest use of t h i s e l ec t rode i s as a cathode

so t h a t t h e processes s tud ied a r e reduct ion processes ,

Very o f t e n t h e reduct ion s t u d i e d a r e those of metal ions ,

when t h e metal i t s e l f forms an amalgam on the su r face o f

t h e mercury drop. I n polarography t h e s i t u a t i o n i s so

arranged t h a t t h e r educ ib le ions a r r i v e a t t h e DNE by

n a t u r a l d i f f u s i o n a lone and t o make t h i s p o s s i b l e , a

"supporting e l e c t r o l y t e " ( o r background o r "base"

e l e c t r o l y t e ) i s added t o t h e s o l u t i o n so t h a t e l e c t r i c a l

migrat ion has 2 n e g l i g i b l e e f f e c t .

Polarography can be used f o r t h e i d e n t i f i c a t i o n of

elements, measurement of concent ra t ion , o r t h e d e t e r n i n a t i o n

I

of oxid-ation s t a t e s of r educ ib le o r ox id izab le spec ies such

as metal i o n , c h e l a t e complexes, inorganic a c i d r a d i c a l s ,

and numerous organic compounds. Trace quant i t i es of chezni c a l

i m p u r i t i e s , and t h e amount o f gases i n s o l u t i o n , redox

p o t e n t i a l s , formation cons tan t s , coordinat ion nunSer,

and k i n e t i c parameters have a l s o been determined. Substances

can be s t u d i e d i n aqueous s o l u t i o n o r i n non-aqueous media,

such as e thanol , methanol, a c e t o n i t r i l e , d imethyl for~amide ,

ammonia, and molten salts .

A simple t reatment of polarographic theory w i l l now be

given.

Consider t h e e l e c t r o d e r e a c t i o n as

Ox + ne- = Recl - - - - - - (1 Ox = Oxidisable spec ies Red'= Reducible spec ies

The I lkov ic equat ion s t a t e s t h a t :

Iti Where id = l i m i t i n g cur ren t i n m i croamps ( p ~ )

a cons tant

number of e l e c t r o n s t r a n s f e r r e d i n r e a c t i o n ( I )

Dif fus ion c o e f f i c i e n t of t h e e l e c t r o - a c t i v e

spec ies

Concentsation of e l e c t r o - z c t i v e spec ies i n

mil-limoles p e r l i t e r .

r a t e of flow o f mercury from t h e dropping

mercury e l e c t r o d e (DME) i n rng per second

t = l i f e t ime of one drop of mercury i n seconds.

A second use fu l equation i s the polarographic wave

equation (111)

Which a t 298 C g ives

Where Edc= dropping e l e c t r o d e p o t e n t l a l

i EL = hal f -nave p o t e n t i a l where i = 2 2

i = t h e cu r ren t i n microamps (PA)

F = 1 ~ a r a d a y (96500 coulombs per equ iva len t )

a = r e v e r s i b i l i t y

Graphs of equat ion (111) f o r var ious values of n are

shown i n f i g u r e s I V - 1 and I V - 2 , It i s important t o note

t h a t t h e polarographic wave equat ion f o r t h e reduct ion of

a complex metal ion i s t h e same as t h e equation f o r t h e

reduct ion of a simple metal ion.

I . . 1

Thermodynamic and polarographic reversibili ty are not

necessarily synonymous. A thermodynanically irreversible

electro-chemical process will always result in an

irreversible polarographic process, but a reversible

thermodynamic reaction may be reversible or irreversible

polarographically, Reversibility in the present discussion

therefore implies polarographic reversibility and not

thermodynamic reversibility. In the irreversible case the

potential no longer depends on the rate of diffusion of the

electro-active substance, so that the rate determining

step may depend on the electrochemical process, on

adsorption at 'the dropping mercury electrode, on some

chemical reaction preceding or following the electro-

chemical process, or on some combination of these.

The simplest test for reversibility is the slope

i of the plot of log versus Edc (equation ( 111) ) , &-

which gives the reversibility parameter a. In fig, IV-2

the proofs of reversibility are in the values

Slope = 0.592 \ Slope = 0,033

Slope = 0.020

n= 1 a=l (reversible)

n= 2 a=O0 88 (irreversibile)

n= 3 a=l (reversible)

The half-wave p o t e n t i a l of complex ions may depend on I

(a) t h e l i g s n d s p r e s e n t , and ( b ) t h e concent ra t ions of t h e

l i g a n d ( s e e t a b l e I V - I ) , For a given l i g a n d , t h e half-wave

p o t e n t i a l s h i f t depends on t h e l i g a n d concent ra t ion , and-

t h i s has been used t o determine t h e coordinat ion nunber

o f complex ions . Equation ( V ) has been der ived f o r a

mononuclear r e v e r s i b l e r e a c t i o n : -

d l o g C, n

Where p = number of l i g a n d s per metal ion

, . Cx = concent ra t ion of ligand-.

The value of p can be obta ined d i r e c t l y from t h e s lope

o f a p l o t of EL a g a i n s t l o g C, . 2

The d i s s o c i a t i o n cons tant of a complex YIm can be

obta ined i n some cases from t h e half-wave p o t e n t i a l of

t h e complex i o n s , and t h e p o t e n t i a l of t h e simple ion

us ing equat ion

complex i t

of a metal which is r

m e t a l l i c s t a t e ( i .e . amalgam) a t t h e dropping mercury

e l e c t r o d e , t h e r educ t ion process may be. represented by

When L ~ - is a b i d e n t a t e l i g a n d , t h i s r e a c t i o n may be

regarded as t h e sum of t h e p a r t i a l r e a c t i o n s

Wher.e pi is t h e o v e r a l l formation cons tant f o r t h e complex

From equat ion ( V I ) i t can be shown t h a t

Where E(c) = half-wave p o t e n t i a l of t h e complex ion 5 E(s) = half-wave p o t e n t i a l of t h e uncomplexed metal

,' ion.

t t IV, ( B ) REVIbW OF POLAHOGRAPKIC STUDIES OF I N D I U M

t

The normal e l e c t r o d e p o t e n t i a l of indium i n aqueous

s o l u t i o n has been de tern ined by Hattox 6 3 a n d by IIakomori 64

who f i n d E=-0.336V and -0,340V r e s p e c t i v e l y , which

p o t e n t i a l i s very c l o s e t o t h a t f o r cadmium, The origina.1-

s t u d i e s of reduct ion of t r i v a l e n t indium ions , us ing

polarographic method i n s o l u t i o n s conat ining c h l o r i d e o r

bromide ion were done by ~ e y r o v s k y ~ ~ , ~ o z z ~ ~ , Kolthoff 62

67 and Schu-fle Indium(I11) i s reduced a t a dropping mercury

cathode t o metzl i n a s i n g l e r e v e r s i b l e s t e p :

No evidence of reduct ion t o d i v a l e n t o r monovalent

s t a t e s has been reported-. The h a l f -wave p o t e n t i a l f o r

indium(II1) however depends on t h e presence of coxplex

forming a g e ~ t s ( l i g a n d s ) . ( S e e t a b l e I V - 1 ) .

Table I V - 1 1

The half-wave p o t e n t i a l of I n ( I 1 I ) a t d i f f e r e n t concent ra t ions

S a l t - . ,

Concentrat ion (M) E l (a) a

KBr 0.20

e t h y l enediamine 1 . 0

ethylenediamine 1.0 1.07

ethylenediamine 2 0 1.30

(a) The p o t e n t i a l i s r e l a t i v e t o a normal calomel e l ec t rode ;

it w a s suggested t h a t t h e s h i f t s i n t h e half-wave p o t e n t i a l

3-x a r e due t o t h e formadtion of indium complex ions InLx

IV, (C) EXPERTMi!'U'AL

A Metrohm Po1arocos.d ~ 2 6 1 ~ rs,?i& polarograph and s.

Metrohm i R Compensator ~ 4 4 6 ( f o r ob ta in ing e r r o r - f r e e

polarograms from low conduc.tivity s o l u t i o n s ) were used

t o obtc.in t h e polarograms. A dropping mercury e l e c t r o d e

with t h e drop c o n t f i l l e r on t h e polarography s t and served

as t h e working el-ectrode (Metrohm EA '53). The re fe rence

e l e c t r o d e w a s a Ag/~gCl e l e c t r o d e (EA 420 Metrohm) i n

0.lA Et4NC10b a c e t o n i t r i l e s o l u t i o n , i n s e r t e d i n t o t h e -

sample so lu t ion . The r a t e of leakage of C104 through

t h e porous t i p of t h e r e fe rence e l e c t r o d e was n e g l i g i b l e '

during a polarographic measurement, A constant

temperature water ba th maintained a t 25+ - O.lOc ~ i s s used

throughout t h i s work t o thermostat t h e e l e c t r o d e hl.

compartment.

The support ing e l e c t r o l y t e , EthXC104, was prepared

by t h e fol lowing procedure, A hot 1 M aqueous s o l u t i o n

of tetraethy1anmoniu.m bromide was added slowly v r i t h

s t i r r i n g t o an equiva lent amount of ho t 0.1M aqueous

s o l u t i o n of sodium p e r c h l o r a t e , Af ter cooling i n an i c e

bath t h e p rec l .p i t a t e was f i l t e r e d o f f on a Buchner

funne l and ~ a s h e d with ice-cold water u n t i l t h e wash-liquid

w a s f r s e from bromide, The salt was r e c r y s t a l l i z e d from

water and d r i e d i n vacuo a t 60•‹ f o r about f i v e hours.

The s o l v e n t , a c e t o n i t r i l e , w a s p u r i f i e d by t h e

method used f o r conductivilty s t u d i e s . 53

De-aeration: t h e e l e c t r o l y s i s s o l u t i o n coulci be

deaera ted completely i n about 15 minutes by bubbling s

p u r i f i e d n i t rogen through i t . Nitrogen was p u r i f i e d

by %he method descr ibed by Meites and Meites. 61.

Due t o t h e high vapor p ressu re of a c e t o n i t r i l e

( ~ a 80mm a t 20•‹) , it w a s necessary t o p r e s a t u r a t e t h e

n i t r o g e n w i t h a c e t o n i t r i l e vapoyr, by passing t h e n i t rogen

throuzh a t r a i n o f wssh b o t t l e s containing a.cetonitri3-e

a t room temperature,

I V , ( D ) RESULTS AND DISCUSSION - The o b j e c t of t h e polhrographic worf w a s t o study

t h e reduct ion o r ox ida t ion , t h e r e l a t i v e s t a b i l i t y and

coordina t ion number of t h e conplexes whose ~ r e ~ a r a . t i o n

w a s descr ibed i n Chapter 111. ' . .

( a ) The s tudy of half-wave -.- p o t e n t i a l s -- and r e v e r s i b i l i t y . ---

Three polarographic reduct ion waves of t h e s e complexes

i n a c e t o n i t r i l e s o l u t i o n with te t rae thyla~monium

p e r c h l o r a t e as a su-pporting e l - e c t r o l y t e showed i n z lnos t

every case a s e r i e s of r e v e r s i b l e o r i r r e v e r s i b l e one

e l e c t r o n t r a n s f e r r e a c t i o n s :

[ p- + e-.Eq3- o r In(11) + e , - I ~ ( I ) second wave I n

. t h i r d w a v e [I$- + e=Lnl4- o r I n ( 1 ) + e e I n ( 0 )

This behaviour i s i n sharp c o n t r a s t t o t h e u.su.a.1

aqueous) p h a s e polarographi c reduct ion

and rzpresen t s reduct ion t o I n ( 1 ) and I n ( 0 ) complexes, and

t h e f i r s t i d e n t i f i c a t i o n of an I n ( I 1 ) complex.

Usually t h e he ight of each reduct ion wave should be

approximately equal i n polarograms , However, t h r e e r e -

duct ion waves were observed, The second wave was genera-lly

10-20% lower than t h e f i r s t , a.nd t h e t h i r d wave usua l ly had

an ~ b n o r m a l l y high l a r g e hump, which might be due t o an

1n (0 complex combining with an in termedia te . Vlcek 69 '

has suggested t h a t such humps r e s u l t from reoxida t ion of

in termedia te products. (F ig . IV-I s o l i d l i n e ) . In o r d e r

t o observe t h i s phenomenon proper ly , a high r e s o l u t i o n

a.c, polarograph was c a r r i e d ou t . (P ig . I V - 3 broken l i n e ) .

i +0*25 1 POTENTIAL E

- Fig . IV-3 The Polarogram of I n (IWT) 5x10 -&,- 1.1

. in H20-!&OH s o l u t i o v , 0.1N LiCl as s u p p o r t i n

e l e c t r o l y t e ,

To g e t a b e t t e r a , c . polarogram a low r e s i s t a n c e I

c e l l must be used , and t h e compound p n ( ~ ~ ~ ) 2 ] - was

t h e r e f o r e d isso lved i n aqueous-methanol s o l u t i o n ( r a t i o

4 :1) with l i t h i u m c h l o r i d e as t h e suppor t ing e lec t ro ly t , e .

Since i n t h e a. c , polarograph (F ig , IV-3, broken

l i n e ) t h e waves marked ( a ) , ( b ) and ( c ) a r e a l l t h e s e m e .

h e i g h t , each of these waves must r ep resen t one-electron

reduc t ions , and we can t h e r e f o r e i d e n t i f y t h e shoulder ,

( c ) as t h e t h i r d wave without any doubt. The wave ( d )

i s consid-ered t o r e p r e s e n t t h e reoxida t ion of an

in termedia te product although t h e a c t u a l compound being

oxid ized cannot be i d e n t i f i e d ,

The d i scuss ion of reduced s t a t e s of metal d i t h i o l a t e

70 - .complexes i s based on t h e r ecen t review by Schrauzer . The Group V I I I Metal Complexes MS4 C4R4 (R=CX, H , CP o r 3 Ph) resemble dithio-quinones i n t h e i r pronounced a f f i n i t y

4 - 2-

f o r e ec t rons . On reduct ion MS4C4R4 and BS4C4R4 a r e -

formed, of which t h e MS4C4R4 anion proved t o be para-

magnetic i n t h e s o l i d s t a t e and i n so lu t ion . S tud ies of

t h e compound [ N I S ~ C ~ P ~ ; ] - conta in ing *i61 .showed a s ~ a l l

hyperf ine s p l i t t i n g i n t h e ESR spectrum due t o t h e

d e l o c a l i z a t i o n of t h e odd e l e c t r o n i n l igand-metal r i n g

orb1 t a l s . "17'* I n a d d i t i o n , i n t h e [ P I ' ~ ( M N T ) J - i o n ,

t h e C-C and C-S bond d i s t a n c e s a r e 1,3568 and l . 7 l O A

r e spec t ive ly . These values a r e in termedia te between those 1

found f o r . s i n g l e and d0ubl.e bonds. In t h e [ K ~ ( N P ; T ) ~ ] ~ -

t h e C-C and C-S d i s t a n c e s a r e 1.33A and 1.75A. It w a s

t h e r e f o r e concluded t h a t t h e unpaired e l e c t r o n occupied

a z-MO de loca l i zed over t h e whole molecule.

The ex i s t ence o f t h e formal lower oxfdat ion s t a t e s

I n ( I I ) , I n ( 1 ) and I n ( 0 ) have been demonstrated i n t h e

pol-arograms, r e s u l t i n g i n t h e reduct ion half-wave

p o t e n t i a l s given i n Tables IV-2,3,4. Following t h e

previous explanat ion , we suggest t h a t i n t h e indiun(II),

( I ) and ( 0 ) d i t h i o l a t e complexes t h e e l e c t r o n s a r e

accommodated i n a r -molecular o r b i t a l de loca l i zed over

t h e whole r i n g system of t h e molecule.

The measured d i f f u s i o n c u r r e n t was found t o be

l i n e a r l y dependent on t h e concent ra t ion of t h e complex

[ I ~ ( M N T ) ~ ] - which i s t o be expected from I lkov ic equzt ion 11.

Fig. IV-4 Concent ra t ion vs Current .

The t h r e e l i ~ l e s d i d no t p a s s t h r o u g l ~ t h e o r i g i n a l p o i n t . due t o i n a c c u r a c i e s i n the concen t ra t ion rneasure;zoni;s.

Chart No 45(2nd wave)

Edc ( v o l t s ) ,.

Tables IV-2, I V - 3 and I V - 4 show t h e half-wave p o t e n t i a l s

f o r t h e c&npleres a t a co rken t ra t ion of ~ x ~ o - ~ H i n '

a c e t o n i t r i l e . The va lues were obta ined frdm equation ( I V )

by p l o t t i n g l o g ( ) a g a i n s t t h e p o t e n t i a l Edc, t h e -i

d i f f u s i o n cur ren t p o t e n t i a l . The equation ( I V ) p r e d i c t s

a s t r a i g h t l i n e with s lope 0.0591 a t 2 5 O ~ . The p o i n t on

t h i s l i n e corresponding t o i = -- id g ives a ~ r e c i s e 2

measurement of t h e half-wave p o t e n t i a l EL, The s l o p e of 2

t h e tangent t o the l i n e shows t h e r e v e r s i b i l i t y and "no

i s t h e number of e l e c t r o n s t r a n s f e r r e d , The half -wave

p o t e n t i a l s , r e v e r s i b i l i t i e s and e lec t ron t r a n s f e r numbers

of a l l t h e indium(II1) complexes and t h e i r adducts which

have been obtained from p l o t s .of El vs l o g ( H

) p l o t s id-i

a r e given i n Table IV-2,3 and 4, A t y p i c a l p l o t i s

shown i n Fig. IV-5.

(b) S t a b i l i t y cons tant s t u d l e s .

Indium complexes E n ( K N T ) - , [1n ( N N T ) 3] 3-, -

k n ( i M N ~ ) ~ ] ~ - - , ~ ~ ( T D T ) ~ ~ , and [ I ~ ( T D T ) ~ ] ~ - have been

s t u d i e d by means of t h e polarographic method i n o r d e r t o

determire t h e s t a b i l i t y of t h e s e complexes which a r e

assumed t o reduce t o indium amalgam i n t h e t h i r d wave,

The r e a c t i o n equation and formation cons tant may be

represented by equat ions ( I V ) , ( V I I ) , ( I X ) , (X) and ( X I )

on page 53. .

The s tandard p o t e n t l a l of t h e Indium ion (E.) i s

equal t o -0.5$ Volt r e l a t i v e t o t h e A g / A g C l e l e c t r o d e

i n a c e t o n i t r i l e ,

The half-wave p o t e n t i a l s ( i n v o l t s ) of t h e complexes

. -1,855 r e s p e c t i v e l y i n a c e t o n i t r i l e s o l u t i o n a t 2'j0 + - 0.1 ,

(See Tables IV-2, IV-3 and IV-4). The formation cons tants

then obta ined from equation ( X I ) a r e given i n the Table IV-5.

Table .IV-I?'

Obviously, t h e o rde r s of t h e s t a b i l i t y of t h e s e comnlexes

I a r e :

I

From t h e s tereochemical po in t of view, it i s a u i t e

2- c l e a r t h a t t h e MNT and TDT'- compounds invs lve i n d i u n ( I I 1 )

i n a f i v e membered r i n g , whereas t h e iKIYT2- compouncl has

a f o u r membered r i n g . Evident ly, R B ? T ~ - and TDT'- complexes

should be more s t a b l e than t h e LPIPLTT compound, 7 2 On t h e

o t h e r hand, t h e MNT complexes a r e more s t a b l e than t h e

2- TDT complexes, probably because MNT has an unsa tura ted

double bond, p l u s t h e s t r o n g e l e c t r o n withdra,wing n i t r i l e

groups which a r e r e spons ib le f o r t h e f a c t t h a t NMT'- r i n g

systems can e a s i l y accommodate a number of valence e lec t rons .

However, t h e u n s a t w a t e d double bond of t h e TDT r i n g system

i s p a r t of a l a r g e p lana r aromatic system, No e l e c t r o n

withdrawing group i s p resen t . This may account f o r t h e

. MET complexes being more s t a b l e than t h e TDT complexes.

Although t h e r i n g system does no t involve a double

bond i n t h e - iMKT compound, added e lec t rons can s t i l l be

accommodated i n t o t h e r i n g because of the two s t rong

e l e c t r o n withdrawing n i t r i l e groups ; t h e e l e c t r o n dens i ty

can presumably d r i f t through t h e double bond toward t h e

n i t r i l e groups,

( c ) Coordination number stu.d.ies.

The purpose of determining t h e coordinat ion number

of t h e MNT and TDT complexes of indium(II1) pol-arographically

w a s t o t e s t t h e p o s s i b i l i t y ' of [ I ~ ( N N T ) 3] 3- and [1n ( TDT) 3] 3-

e x i s t i n g i n so lu t ion . According t o equat ion (v) , t h e value

of p can be obtained from t h e s l o p e of a p l o t of t h e

half-wave p o t e n t i a l a g a i n s t t h e logari thm of the l i g a n d

concent ra t ion: t h e t h i r d wave half-wave p o t e n t i a l w a s

chosen f o r t h i s purpose. The d a t a and s lope a r e given

i n able IV-6,? and Figure IV-4,5,

Plot of EL(volts) 2

Concn. of KNT(N)

Table IV-6

ve r sus M.RTT*- concentration f o r [I~(!:NT) 'I3- ' 3 '

-El V (third wave) id (amps x lo-' ) 3-

Table I V - 7

2- P l o t of volts ) versus TDT concent ra t ion f o r [ ~ ~ ( T D T ) 3] '-. 2

Concn. of TDT(14) E l V (first wave) id (amps x Z.-

4x1 0 -" +0.175 98

The s o l u t i o n contained a small amount of abso lu te methanol.

. -

4

I

0,40 P ,60 0.80 l.GO 1.20 1:40 10@i;I~iT . . - .

5 Fig. IV-6 Title 3s for Table IV-6 P f . ,

*

-.lo . 0.03 +.13.20 -- 0.30 0.40 ~ 5 0 . 0.60 0.70 0.80 log concn, TDT

Fig. IV-7 as f o r table IV-7

. From t h e experimental r e s u l t s t h e p value i s 3 . f o r

both t h e MNT and TDT complexes x i t h i n experimental e r r o r , 5

The compound ~ ~ ( M N T ) 3]3- has been prepared as e

c r y s t a l l i n e sa l t , but t h e [I~(TDT)~]~- anion could n o t

be. i s o l a t e d poss ib ly because t h e l igand TDT i s e a s i l y

polymerized as an o i l i n a i r . This may a l s o be t h e reason

for t h e lower p value,

CHAPTER V - I

RESULTS AND DISCUSSION, - - V. ( A ) COIVDUCTIVITY - -

u The r e s u l t s of molar conduct iv i ty meas~ements f o r

var ious e l e c t r o l y t e s have been c l a s s i f i e d f o r a c e t o n i t r i l e ,

nitromethane, acetone and. o t h e r s o l v e n t s , and t h e value of

t h i s method i n i n v e s t i g a t i n g t h e i o n i c na tu re of complexes

i s well. e s t ab l i shed . T'ne va lues f o r 1:l e l e c t r o l y t e s i n

ni'tromethane ha.ve been repor ted t o be between 100 t o

-1 2 ,120 ohm cm mole-' by Fergusson 2nd Nyholm 73. The

conduct l .vi t ies of the MNT complexes E t 4 N P ~ ( N N T ) ~ , Et4N N ~ , ( M E ~ T ) ~ and Et4N A ~ ( K F T ) ~ have been found t o be

83, 81 and 80 ohm-1cm2rnole-l r e s p e c t i v e l y , showing them

t o be 1 :1 e iec t ro ly t , e s i n nitromethane; f o r t h e 1 : 2 -

e l e c t r o l y t e s ( E ~ ~ N ) ~ [ T ~ ~ ( F ~ K . : T ) ~ ] and ( E ~ ~ N ) ~ ~ F ~ ( w B T ) ~ ] ,

t h e va lues a r e 307 and 320 ohm-1cm2mole-1 i n acetone

s o l t u i o n .

The conductance r e s u l t s of LENT complexe8 i n

nitromethane a r e f o r 1 :1 e l e c t r o l y t e s 61 ~ h r n - ~ c m ~ r n o l e - ~ ,

f o r 1- 12 e l e c t r o l y t e s around 2.50-175 ~ h r n - ~ c m ~ r n o l e - ~ , and

f o r 1 8 3 e l e c t r o l y t e s 200-210 ohm-lcm2mole-l. The only

conduct iv i ty value repor ted f o r a TDT complex i s f o r

I- ( ~ - B U ~ N ) ~ . V ( T D T ) 3] f o r which n i s 122 ~ h r n - ~ c r n ~ m o l e - ~

i n nitromethaneo Table V-1 g ives t h e r e s u l t s on t h e n o l a r

conduct iv i ty of I n ( I I 1 ) d i t h i o l a t e complexes with MNT, LKNT,

and TDT and t h e i r adducts , i n z c e t o n i t r i l e a t room temperature,

The conduct iv i ty of d i

Complexes

E ~ ~ N [ I ~ ( M N T ) ~ (dma)d

(Bu41J ) [in (LIQT ) ~l]

( R U ~ N ) ~ ~ I ~ ( ~ - N R T ) 2 ~ 4 (Bu4N ) [1n (&NNT ) I]

(SLI~N ) 3 [ ~ n (&KNT ) 3l (Bu4R) [1n (;KNT) 2pheq

( B u ~ N ) [ ~ n ( i I W T ) ~ b i p J -

E ~ ~ N @n ( TDT J EC4N k n (TDT ) 2phen]

Et4N ~ ~ ( T D T ) p b i p ~

Tab1 e V-1 ,

t h i o l a t e complexes of Indium(II1) .

Conductivity E l e c t r o l y t e

141 1 :1

-79-

The values i n T ~ b l e V-1 f o r t h e complexes of i r d i u m ( I I 1 )

d i t h i o l a t e s and t h e i r addbcts a r e c lose t o those repor ted

by e a r l i e r workers. A comparison of t h e value of t h e MNT

and - iNRT compounds show t h a t MIW complexes have h igher

c o n d u c t i v i t i e s ; t h e lower c o n d u c t i v i t i e s of t h e LKKT

compounds may be due t o t h e lower mobi l i ty of t h e very 3.

l a r g e Bu4N ca t ion , The conduct iv i ty of (Et4W)2 L~( :&:RT)~- o x i n e l i s lower than t h a t f o r a 211 e l e c t r o l y t e , and.

IL B U ~ N [ I ~ ( ~ M N T ) 2pheq and Bu4N k n (UIST) 2 b i p d have

conductivf t i e s similar t o those of 1 :1 e l e c t r o l y t e s ,

The most i-mportant conclusion of t h e conductance r e s u l t s

i n t h e t a b l e i s t h a t t h e s to ich iomet r i e s and i o n i c

formulat ions of t h e compounds are c o r r e c t . <

2 0 - 1 1 ! I

V. ( B ) THE INFRARED SPECTRA O F INDIOlrl DITHIOLATE COWLEXES I

Y

AND THEIR ADDUCTS I

-- Although s e v e r a l t r a n s i t i o n metal d i t h i o l a t e complexes

a r e known, l l t t l e a t t e n t i o n has been paid t o d e t a i l e d ' -

i n f r a r e d s p e c t r a l s tud ies . ~ ) ~ v i s o n et ,I., '* have assigned N

I bands t o Z / ( C = C ) i n some complexes of t h e type @ 1

[ N ( s ~ c ~ ( c F ) )4"-, b i t h W = N i , Co, Fe, Pd and Pt, and 1

3 2 t

m=2 o r 3, n = O , 1, o r 2 ) . Schrauzer and Nayweg 75 have

e partial ly assigned bands f o r [&!I (c2s2fi2) 2- (R=H, We and Ph) . The most r e c c n t work i s t h a t of Adarns and Cornell 76, who

made more complete I R s t u d i e s of t h e complexes

(R=H, CF andCN; M = ? X I , Co, Cu, P d a n d P t ) . 3 Their assignments depend i n p a r t upon those of e a r l i e r

workers,

The s ign i f i can t , IR' absorption bands of t h r e e s e r i e s

of complexes prepared w i l l be d iscussed and compared t o

each o t h e r , with emphaSis on the stretching modes of - t h e

-CN group in MNT and LNNT complexes, a n d on t h e )/(C=C) , Y(C=S), andY(~-S) modes i n genera l ,

The s i g n i f i c a n t bands of t h e i n d i ~ ~ m ( I ~ l ) IiKT, LKWT

and TDT complexes a r e tabul-ated i n Tables V-2, V-3, and

V-4 r e s p e c t i v e l y ,

The i n f r a r e d s p e c t r a of t h e var ious - MNT compJ.exes

(Table V-2) c l e a r l y show t h e presence of j /(~sl\J), Y(C=C)

and Z/(C-S) bands, The i nd iv idua l bands of t h e MNT complexes

can now be examined. F i r s t l y , the (CZN) band.s at

C

-81- Table V-2 . I .Re ebsorptiqn frequencies (CE-')

. f o r MET compl-exes -

C . -$2 - 1 I

Table V-2 I R Absorption Frequencies ( cn - l ) I I I

for NXT Cor:lplexes ( cont . ) -

Na2i4NT E n (WNT) ,-phcg- p n (i4NT) e n (I.iifT) ( d m ) J' p n ( b l i ~ ) ox&e -. +

33x0s 365Sm

Table

V-3

IR Absorption rrequencies(c;')

for - i\tN

T Comp

lexe

s

X =

C1, Br,

or I.

Table V-4

IR Absorption Frequencies fo

r TDT Ccmplexe

s

TDT

approximately 2200cm-' are p r e s e n t i n a l l t h e comp1.exes

2- with l i t t l e o r no s h i f t from t h e spectrum of KNT i t s e l f ,

c l e a r l y i n d i c a t i n g t h a t t h e n e u t r a l donor (e.g. b ipy , phen,

en, and ox ine ) has no inf luences on t h e C r N group.

Secondly. Y (c=c) i s normally i n t h e region 1600-1680cm-~,

b u t Y ( C = C ) i n our MNT complexes f a l l s a t 1430-1480cm-~,

sugges t ing t h a t t h e double bond charac te r i s reduced du.e

t o d e l o c a l i z a t i o n of t h e x-bonding system ( t h e r i n g system).

The )/(C=C) frequency i n t h e f r e e l igand KNT'- is a t

1450crn-~, and Adams and Cornel l 76 b e l i e v e t h i s i s due

t o t h e a n i o n i c n a t u r e of IVINT~- .

T h i r d l y , , t h e two Y(c-S) bands which a r e known t o be

i n t h e regions 1105-1120~m-~ and 860-873cm-1 i n t h e

compound Ni(S2C2HZ)2 and M(P?NT)~ ( N = N i , Cu, Pd o r P t ) ,

75 have been ass igned by Adams e t a1. 57 and Schrauzer e t al. . I n t h e complex [ I ~ ( N N T ) ~ ] - , - t h e r e a r e two bands a t 11-15cm-'

and 1150~111-' and one very s t r o n g band a t 855cm-l, be1 i eved

t o be (C-S) s t r e t c h i n g modes. The adducts have similar '

bands i n t h e same reg ions , and no s i g n i f i c a n t changes a r e

not iced between [ I ~ ( K K T ) ~ ] - and i t s adducts ( see t a b l e

Four th ly , t h e range of Y(M-S) has been reviewed by

Adams and Cornell 76. The h i g h e s t va lue , 480cm-l, i s

found f o r [MO-S~] 3- h u t more t y p i c a l i s t h e range

440-300cm-~ f o r uni- o r d i v a l e n t d i t h i o l a t e l i g a n d complexes.

- For t h e . I n ( l 4 . N ~ ) ~ comp1,ex and i t s adducts t h e s t rong

bands occur around 310-320cm-l; with [ I ~ ( M N T ) ~ ] ~ - t h e

band occurs a t 292cm-I. These band3 aSe assigned t o t h e '

Ij(1n-S) v ib ra t ion . Medium i n t e n s i t y bands lower than

(In-S) a r e noted a t 306, 309, 300 and 318cm-1 i n t h e

complexes [ I~ (KNT) 2phen]; [ ? n ( F l ~ ~ ) 2bipy] -, [ ~ n (NNT) -

and [ I ~ ( N N T ) *oxinel- r e spec t ive ly . In t h e 200cm-~ region

another new band i s observed a t 220-~80cm-~ which i s

t e n t a t i v e l y assigned as an indium-nitrogen v i b r a t i o n .

This w i l l be discussed l a t e r ,

It i s well recognized t h a t t h e v i b r a t i o n a l s p e c t r a

of t h e f r e e l igznd - iNNT and i t s com~lexes a r e very - similar t o t h a t of I ! K T . ~ ~ ' ~ ~ The v i b r a t i o n a l bands of

iNNT and i t s complexes a r e t e n t a t i v e l y assigned i n - Table V-3. The ~ ( C ~ T ) bznds i n a l l t h e - i N N T cmplexes

a r e a t 2200bm-~ as i n t h e )INT s p e c i e s , so t h a t again t h e

n e n t r a l donprs ev ident ly have no inf luence on t h e (czI'?)

s t r e t c h i n g mode. The C=C s t r e t c h i n g frequency i n t h e

f r e e l i g a n d , F V T , i s a t 1620crn-~ bu t i n t h e complexes

t h i s f a l l s t o 1480 t o 1490crn-~. The reason f o r t h i s

lowering frequency of ( C = C ) might be s t r a i n i n t h e

S, C==C& 2 r i n g lowering t h e double bond. frequency, 78 S

On comparing t h e Y(c-S) v i b r a t i o n of - iMNT corn2lexes

@76cm-l) and t h e correspondicg I~/!,INT complexes

(860crn-'), one f i n d s t h a t Y(c-S) is higher i n t h e - iRNT

I

c a s e o B probable explanat ion i s i n terms of t h e r i n g

s t r a i n e f f e c t which r e s u l t s i n a higher energy f o r t h e

f o u r membered than f o r t h e f i v e membered r ing . There

a r e two new bands a t 350-370cm-1 and 230-23$cn-l i n the

i M N T complexes but nc bands were observed, below 350cm-1 - f o r [ I ~ ( ~ I . , ' ~ N T ) J3-. Following t h e e a r l i e r d i scuss ion ,

J

t h e indium-sulphur bands should be i n t h e 300cm-I .

region , b u t t h e (In-S) bands of G N T complexes were

found i n 350-~70crn-~ region, which is a l i t t l e higher

than f o r t h e EBT com~lexes .

The I . R . s p e c t r a of t h e t h r e e ( S U ~ N ) ~ [ I ~ ( ~ P : N T ) ~ X ] - compl-exes ( X = C ~ , B r , and I ) a r e nea r ly i d e n t i c a l except

f o r t h e chloro conpound which has an absorpt ion band

a t 220cm-l, probably $(In-Cl). The value of Y(1n-cl)

i n var ious compounds has been ass igned t o t h e 200-~00cin-~

reg ion by o t h e r workers. 79980

The i p f r a r e d bands of TDT and i t s complexes - with

indium(II1) a r e t e n t a t i v e l y assigned i n Table V-4. The

major changes found on complex formation a r e t h a t

t h e )(s-H) band a t 2545crn-I d isappeers on coordina t ion ,

and t h a t t h e r i n g v i b r a t i o n bsnds a t 1594, 1590 and

1650crn-~ a r e a t l o v r ~ r f requencies i n t h e complexes.

However. t h e f requencies of P(c-S) a r e lower i n t h o

complexes than i n t h e f r e e 1j.gan.d. The reason f o r t h i s

is not cl e,n.r.

Very.recently indi~n~nitrogen vibration bands

have been assigned by Patel and ~ u ~ k ~ : The y(1n-WCO) vibration is in the 330-350cn-l region. With donor

ligands such as pyridine and 2,2! -bipyridyl, )/ ( ~ n - B ) is

at 200-235cm-'repion. Following the eariler workers,

the )'(In-M! vibrational bands of indium dithiolate

complexes with l,l0-phenanthroline and 2,2'-bipyridyl

with I~iflT, - iI4NT and TDT, and with ethlylenediamine, N,N'-dirnethylacetarnide and oxine with PZnJT are tentatively

assigned in the region 223-280crn-l.

Table V-5 records all assignments of metal-ligand

vibrations for the three series of complexes. As

noted above, in the bidentate neutral adducts and the

oxine complexes the y(1n-S) vibration appears as two

bands (see Table V-5).

Table V-5 Coniparison of Indiuni-ligand Vibrat ional . Frequencies f o r ~ n d i u m ( ~ I I ) ~ t ~ i o l a t e

and I ts iidductsc (an-')

Complexes

Et N Jn (IGNT) 2biPY] 4. C- Et N [In(lGWi') 2en] 4 -

( E t N) I n (i4NT) 2oxino] 4 2 C - - E ~ ~ A ~ ~ ( I W ? ) ( d m ) ;I

( BuqN) [1n (5.1-iRT) - (Bu 4 N ) 3[ I ~ ( ~ X A T ) ~ ] - Bu4N [ ~ n (ilGIIT) 2Phen]

X = C1, B r , o r I.

C

-90-

V, ( c ) THE Ns4H SPECTHA STUOY OF 1 ,lo-PHENAilTTEROLINE --

AND 2 ,2 '-BIPYRIDYL I N I X D I U I i (111 ) DITBIOLATE COPPLU.ES, -- - - - r The NKR s p e c t r a of t h e complexes Et4N L I ~ ( B W T ) 2-phen],

Et4N [ I ~ ( ~ N T ) 2b ipd , Bu4N ~ ~ ( L N M T ) 2biPd, Et4E ~ ~ ( T D T ) p h e g , and E ~ ~ N [ ~ n ( ~ ~ ' T ) ~ b i ~ y ] were s t u d i e d i n o rde r t o o b s e p e

and deshie ld ing e f f e c t s on t h e protons of 1 , lO-phenanthrol ine

and 2,2 ' -bipyridyl on complex formation. It a l s o proved

i n t e r e s t i n g t o i n v e s t i g a t e t h e s tereochemistry of sone

s p e c i e s i n terms of t h e c i s and t r a n s conf igura t ion of

t h e TDT methyl group i n these complexes.

The NMR s p e c t r a of 1.10-phenanthroline i n acetone 81

and 2,2 ' -bipyridyl i n dichloromethanee2 had been

repor ted previous ly . The p resen t work has repeated t h e

measu.rement of 1 , lO-phenanthrol lne and 2 ,2 ' -b ipyr idyl

i n dmso. The s p e c t r a l d a t a a r e i n Tables V-6

and V-7.

The e i g h t protons of 1,lO-pha-nanthroline and

2,2 ' -bipyridyl can be considered as f o u r p a i r s , v i z ,

H a and H a 8 , Kb and Hb' , Hc and Hct , and Hd and Hd' which

behave a s equivalent p a i r s g iv ing orle resonance

s i g n a l from each pa i r . '

The chemical s h i f t d a t a f o r t h e protons of t h e

indium(II.1) complexes of phen and bipy with MXT, 'iFXT - and TDT'run i n d-mso-d6 s o l u t i o n a r e recorded i n

Table V-b and V-9.

Table V-6

Ni3R data f o r I, 10-phenanthroline in dmso at 6Wc/sec.

Proton

ka

Chemical Shift

(cps down field from 'iTdS)

M.12 data f o r 2,2'-bipyridyle i n d n ~ o a t 60?.k/sec.

Chemical S h i f t

( c p s dcwn f i e l d f r o m Tl<S)

Table V-8 I

i n dmso-d6; chemical s h i f t cps downfield from TBS.

- - brange c r y s t a l - 574 bIia=20 / 561 &i!a= 7

A Ha= Ha(phen complex) - H a (phen) . Orange c r y s t a l s ; t h e -CH s i g n a l o f TDT a t 11.5 and 117cps 3

(two peaks )

Yellow c r y s t a l s ; t h e -CH signs1 of TDT show only one 3 peak a t 113cps.

Ha, Ha'

Hb, Hb'

Hc, Hz'

Table V-9

NMR data of indium d i t h i o l a t e b i y y complexes i n dmso-clL ; cheiiiical shirt cps doimfie!-d from TXS

LJ

It i-s q u i t e c l e a r frbm t h e d a t a i n t h e t a b l e s t h a t

i n t h e d l t h i o l a t e complexes, t h e e i f ~ h t p ro tons of

1 , lO-phemnthro l - ine o r 2 , 2 * - b i p y r i d y l s t i l l s h o i ~ t h e

same . resonance p a t t e r n , and. t h e pro ton s i g n a l s show

v s r i o u s downfie ld s h i f t s . This downfie1.d s h i f t

(i. e , decreased s h i e l d i n s ) i s presunably cai~.sed. by t h e

c o o r d i n a t i o n o f t h e n i t r o g e n atoms t o t h e cen t ra l .

metal ~ n d i u m ( I l 1 ) . S ince e l e c t r o n i c charge i s withdrawn

toward. t h e n i t r o g e n from all p o s i t i o n s i n t h c ri.ng, a

downfie ld s h i f t of t h e resanznce o f a l l t h e p r o t m s

is observed.

It is i n t e r e s t i n g t o compare t h e downfield s h i f t

of t h e f o u r p a i r s of p r o t o n s , occu r ing i n t h e o r d e r

~ H ~ Q A H c B CHd>DUa i n [ ~ n (PINT) 2 p h e g - and [ ~ n ( i ~ ? T & ~ h e n ] - , - and t h e o rde r d I I c 5 4FibZ dHa*AHd i n [ ~ n (TCMT) 2bipy)- snd

[ ~ n ( i ~ E ~ ) ~ b i ~ d - . - I n o t h e r words t h e b i g g e s t d e s h i e l d i n g

e f f e c t i s a t H b and Hc i n t h e 1- , lo -phenanthro l ine

complexes and a t Hc i n t h e 2 ,2*-b ipyr i r ly l complexes.

It seems p o s s i b l e t h a t t h e e l e c t r o n d i s t r i b u t i o n i n t h e

r i n g systems i s e q u i v a l e n t t o e s t a b l i s h i n g a d i p o l e t o

t h e n i t r o g e n atom from Eb and. Kc p o s i t i o n s i n

1 , lO-phenanthro l ine complexes a.nd from t h e Hc p o s i t i o n

i n 2 ,2 ' -b ipy r idy l complexes. (See F igure V - 1 ) .

F i g . V-l

The d i p o l e d i r e c t i o n i n l , lO-phen~ .n th ro l ine

A comparison of A H a ; AHb, AIIc and A H d for the

1,lO-phenanthroline and 2,2f-bipyridyl conpounds shows th2.t

the AHa, etc values of 1,lO-phenanthroline are big2e-i. than

for the 2,2t-bipyridyl case. This may indicate that

more strongly coordinated indium

than 2,21 -bgpyridyl. However, in the l,l0-phenanthroline

and 2,2'-bipyridll conpluxes wi th LI~(TDT) 21- the chemical

shift of the f ~ i r pairs of protons seems to he the same

in both cases. The reasons for this arc not clear at -

present.

The stereochemistry of [I~(TDT) 2 ~ ; pn (TDT) 2phen] - and [~n (TDT) 2bipy]- has been investigated from the NIR

spectra. The complex [1n (TDT) 2]- has two possible

configurations, cis and trans, but only one sign2.l was

recorded at 128 cps (or r = 7 . 8 4 ) wlnich is to be expected

since the two methyl groups in the complex [I~(TDT}~]-

have the same environment, (see Figuration V-2)

However, in the complexes [I~(TDT) 2phen) - and [~(TuT) 2biPy]- there are tvro possible methyl conf iguretions

depending upon molecular s tereochemistry . (1 ) If [I~(TDT)~] - in the tians conf igurztion coordinate

- - .

with 1,lO-phenanthroline, both the methyl groups of

the TDT ligands will be in the same enviroment,

( 2 ) If [I~(TDT)~]- in the c i s configuration coordinate

wi'th 1,lO-phenanthroline, the methyl groups of the

TDT ligands will not bo th be in thn same envSronrqeqt,

(See Figure V-3) .

i compounds, obtai~yed as orrlcge c r y s t a l s and yel-1-ow C ~ Y F ~ R ~ s

i and t e n t a t i v e l y i d e n t i f i e d as two i soners . The f3rmer

shows tvo methyl group r e s c ~ ~ a n c e s a t 11-8.5 and 1 1 7 cps

i n :TMR spectrum, while t h e yellow one shows only one

methyl peak a t 123 cps. The yellow [ ~ n ( ~ ~ ~ ) ~ o h e d - might t h e r e f o r e be t r a n s , and t h e orange L1n ( ~ l 2 ~ ) ~ ~ h e d - t h e c i s isomer.

The c o m ~ l e x [ ~ n ( ~ ~ ~ ) ~ b i p y ) - gives only orange c r y s t a l s ,

and t h e methyl group nTN8 s i g n a l i s a, s i n g l e t a t 127 cps .

There a r e t ~ i o p o s s i b i l i t i e s t h a t can be su-ggested.

(1) The b ipyr idy l c.omplex may e x i s t as a t r z n s

conf igura t ion only.

( 2 ) In t h e b ipyr idy l s t r u c t u r e t h e r e i s a s i n g l e

bond between two r i n g s which can t h e r e f o r e r o t a t e ,

i n which case thc methy l groups could hzve the

same envi?-onmen t , I

V (D) THE UV SPECTRA OF INDIIJF DITTIIIOLtATES AND THEIR --- ---- -- - ADDUCTS . --

The two main purposes of u s i n g UV spectrum i n t h i s

work were t o ( a ) s tvdy t h e format ion of c o m ~ l e x e s of

[ r I n ( l " l ~ ~ ) ;I - with n e u t r a l donor l i g a n d s by ~ 0 b . l ~ method,

and ( b ) t o s tudy t h e p r i n c i p a l a b s o r p t i o n s of indium

d i t h i o l a t e compl-exes and t h e i r adduc t s ,

(a) The s tudy of e l e c t r o n i c s ~ e c t r a of t h e Indium --.-------.--- .- -.- ----- ---

The uv s p e c t r a of h i ( ~ ~ ~ ) ~ * - and [ P ~ ( T ~ N T ) ~ ] ~ - e t c .

have been re:mrted b y Shupack e t who f i n d f i v e

maxima i n t h e r e ~ i o n 10,000-5000cm-~ (F ig . V - 4 ) . Four

o f t h e i n t e n s e bands have been ass igned t o t h e charge

t r a n s f e r t r a n s i t i o n s M+L o r L--tM and L-+L-s, a.nd t h e

scheme diagrali! and e l e c t r o n i c s ~ e c t r a (F'ig. V-j), Table V-10)

are taken .from Shupack and Gray's work 39 ,e3

Fig. V-L+ ~ m p o r k a n t molecular o r b i t a l energy l e v e l (i41:T) dn- -

M o r b i t a l s - 'MI,, O r b i t a l s

ant ibonding

L O r b i t a l s

/

i% bonding,non bonding

Fig. V-5 S i q l e energy l e v e l sclieme f o r square p l a n a r c o q l e x e s , 39

Table V - I 0

E lec t ron ic Soectra of i:,(???r) 2- - - -L__ -.--- ---_I - Com~l ex es 39 2--

Transitians

d-d - 1 3 A + B

€3 g 2 2 ' no t observed.

(x -y -XY)

1 3 Ag-+ B @; not observed

L--M Charge --- Transfer

not observed

not o3served

not observed

not observed.

not observed

I

I n t h e spectrum of [ I ~ ( P B T ) ~ ] - t h e r e a r e t h r e e

4 i n t e n s e bands a t 28400crn-' (6=l, 6x13 ) , 29400cm-'

t h e symmetry o f t h e compound cannot be decided a t t h i s

s t a g e . Following Shupack9s work, however, t h e t h r e e

bands have been t e n t a t i v e l y a s s i s n e d accord ing t o t h e

energy l e v e l and e x t i n c t i o n c o e f f i c i e n t , The two bands

a t 28400cmd1 and 29500cm-I a r e L ( 'IC. )-PI and L ( w )d#,

charge t r a n s f e r r e s p k c t i v e l y , and t h e band a t 29400c-o-I

i s L ( $ )-J/L(!$*), The L-+M t r a n s i t i o n may i nvo lve

t h e l i g a n d and br>nding o r non -bond i~g e l e c t r o n s

moving t o i nd ium( I I1 ) 5 d empty e orbits-1s. If t h e 15

E ~ ( M R T ) J - i s t e t r a h e d r a l , a s imp le scheme may be

drawn as i n ~ i g u r e V-7 fo l lowing Gray's work. 39 The

spectrum of [ I ~ ( F M T ) J - i s shown i n F igure V-6. '

I n ( S ) o r b i t a l s 4 L o r b i t a l s

bcndinginon- -I----, % bonding

I bonding . 1

1

Fig . V-6. Simple energy l e v e l scLlerne for

t e t r a h e d r z l indium complexes

Three i n t e n s e a b s o r t i o n bands were o3served i n

[ ~ ~ ( T D T ) ~ ] - complexes, bu t , no p rev ious a s s i g n r e n t s f o r . T13rT corn??-cxcs a r e a v a i l a b l e .

The UV s p e c t r a of t h e complexes of N i ( I I ) , Pt(lI),

Pd(III), C u ( I I ) , Zn(II), ~ ~ ( 1 1 1 ) arid Fe(I1) with I W T - have been thorough1.y s t u d i e d b y Werden e t and

Fackl 'er e t They assumed t h a t b ; i ( i ~ ~ ~ ) - 2 ' [ P ~ ( ~ F N T ) ~ ] ~ - , [P~(L~~!HT);) 2.-, and [~u(i!b:h'~)

3 '- - - 4 - have

DZh symmetry, and t h a t [ ~ e (il9YT) - 3- and P o (iPTT) ] 3- - 3 a r e octa ,hedral , and then asrigfled t h e a b s o r p t i o n bands

of t h e complexes as shown i n Tahle V-11.

Table V-11

Electronic Spectra of M-IMKT - Complexes in CH,CI4.

max ( cm-I ) J

Assignment

d--d

M - r L s

L-4-L*

o * .

-111-

The visible s p e c t r a of t h e t h r e e comnoimds b

[ I ~ ( & K N T ) ~ X ] 2- ( X = C ~ , B r and I )

I F . w i t h i n exper imental e r r o r , wi th

(F iguse V-9) a r e i d e n t i c a l

a b s o r p t i o n bands a t

and 38600crn-~. Following

Werdenls work, tkeband a t 29200cm-I and 38600crn-' nay be

a s s igned t o t h e L--+L* t r a n s i t i o n . The UV spectrum of

[ I ~ ( ~ E K T ) 3]3- has f o u r i n t e n s e bands ( F i g u r e V-9). t

Two bands a t 29600 and 38600cm-I may be a s s igned as

L--+L* t r a n s i t i . 3 n on t h e b a s i s of ene rg i e s and e x t i n c t i o n

c o e f f i c i e n t s .

( b ) Stud-ies of Com~lex F_ormatiop i n S o l u t i o n .

The s p e c t r o s c o p i c method has been used ex t ens ive ly

i n i n v e s t i ~ a t i o n s of complex format ion and t h e ~ e a s u r e n e n t

o f fo rma t ion c o n s t a n t s . J o b ' s method has been used i n t h e

p r e s e n t work, ~ i t h t h e a s s lmp t ion t h a t only one complex

was p r e s e n t i n s o l u t i o n :

L" = phen, b i p y , ox ine o r en.

When a n e u t r a l b i d e n t a t e l i g a n d . L" w a s add-ed i n

s o l u t i o n t o t h e [ I ~ ( M F T ) ~ - complex i n t h e r a t i o --

[ I ~ ( x R T ) ~ ] - : L" = 1 : O . 1 : 0 . 5 , 1 1 . 0 1 :2 .0 and 1 : 3 . 0 ,

t h e W spectrum shovred t h a t t h e combining r a t i o of [ I~(KNT)~]-

wi th L" w a s 1:l ( s e e F ig . V-10).

300 325 3 50 4.00 45Omp

F i q . V-10

The a b s o r p t i o n spec t ru l r of [ I ~ ( > s T ) ~ ] - with d i f f e r i n g

amounts of I., 1 0 - o h e n a n t l ~ r o l i n e

(1) [ I~ (AI \ :T )~ ] - : phen = 1 : O . O (mole r a t i o )

( 2 ) = 1 : 0 . 5

( 3 ) = l r l e 0

(4) = 1 - : 2 e C

( 5 ) = 1:3.0 - The c o n c e n t r a t i o n of I ~ ( K Y T ) ~ i s 5x10 -b M i n a c e t o n i t r i l e ,

The two bands a t 2840,Ocrn-I and ~ ~ b 0 3 c r n - ~ disappeared

as t h e b i d e n t a t e l i g a n d w s added (1 .e. f o u r coo rd ina t e

s t r u c t u r e wss changing t o pseudo-octahedral s i x coord-inate

s t r u c t u r e ) . Two new bands were found i n t h e 27000-

29000cm-1 r eg ion ( s e e Table V-12).

The UV s p e c t r a of t h e k n (TDT) 2] - and [ .In(i l~?i ' ) - 2 ~ ] '- complexes were not d e t e c t a b l y changed du-ring t h e addLtion

of t h e b i d e n t a t e l i g a n d . The abso rp t ion Sands of t i e

ind.ium(I11) d i t h i o l a t e complexes a.nd t h e i r a,c?duc.ts m e

l i s t e d i n Table V-12.

T a b l e V-12 - The UV spec t ra o f Indium hithiolate complexes i n CH CW.

3 - Compound mx ( c m - I ) € Assignmert

Table V-12 cont .

J - En ( IWT ) ( dma ).

27800 1 1 . 1 ~ ~ 1 0 ~

Table V-12 cont .

V ( E ) STHUC'I'iTRfLL LJISCUSSION -

The s t r u c t u r e of cam6lexes of d i t h i o l a t e 1-iyands

2- PXT , T D T ~ - , S2C2Ph2 and ( s ~ c ~ H ~ ) ~ - with t h e t r a n s i t i o n

metnl ions N ~ ( I I ) , C o ( I I ) , C O ( I I I ) , Cu . ( I I I ) , A u ( I I I ) ,

V ( V I ) , Re(VI) , e t c . , have been determiced by x-ra.y

c r y s t a l l o g r a p h y - 52 t771 84,, The complexes have coo rd ina t l on

numbers of f o u r , f i v e , and s i x . The geometry 'of a l l t h e

f o u r c o o r d i n a t e complexes s t u d i e s showed that t h e su lphur

atoms surround t h e m e t a l s i n an e s s e n t i a l l y sql lare-planar

s t r u c t u r e . The ccmplexes of co ( I11 ) a ~ d Fe(111) exist

as bo th f i v e coo rd ina t e mononers amd f i v e coo rd ina t e

dimers . The f ivt. coo rd ina t e compl-exes of [CO (BXT) 2 p ~ -,

[ ~ e ( 1 . i ~ ~ ) py] - and [CO (#KT) 2PPh 4 - have t h e proposed

squa re pyramidal s t r ~ c t u r e * ~ shown i n F igu re V-11 .

Fig. V - l l

Proposec' s t r u c t u r e of t h e ~ h o s ~ h i n e a.dducts gf

MFT comnl exes.

The s t r u c t u r e of t he d imer i c form of t h e conplexes

a r r a n c e ~ e n t of t h e f i v e coo rd ina t e s squa re pyrzmid.al

dimersR6 i s shown i n F igu re V-12.

F ig . V-12 ------...- --

The dirceric s t r ~ x c t u r e of YNT cqrlnl exes.

The s l x c o o r d i n a t e complexes e . g. V(S2C2Ph2) 3, ,

# D ( S ~ C ~ H ~ ) ~ , e t c . , have been found t o h r v e p e r f e c t o r

n e a r l y p e r f e c t t r i g o n a l p r i s m a t i c s t r u c t u r e s ( s e e

diagram on page 23 Fig . 11-2) .

I n t h e compound [CO (FET) 2phen)-, t h e s i x c o o r d i n e t i o n

85 i s a p p a r e n t l y n o t o c t a h e d r a l . Corn~lexes o f - iMNT s t u d i e d by Fackler70 wi th t h e

b i v a l e n t i o n s N ~ ( I I ) , Pd(11), ~ t ( 1 1 ) and ~ ~ ( 1 1 ) adre

squa re -p l ana r . With t r i v a l e n t i ons [ ~ e ( 1 1 4 ~ ~ ) 1- and 3 [CO(LNNT) S] - i t i s p o s s i b l e t h a t t h e su lphu r atoms a r e

a r r anged e i t h e r i n a t r i g o n a l - p r i s m a t i c o r a n octahed-ra l

c o n f i g u r a t i o n . The W and I R s p e c t r a of L c r ( i P 1 ~ ~ ) , - 31- which i s isomorphous wi th t h e F e ( 1 1 I ) and Co(111) c?zp l exes ,

s u g g e s t s s t r o n g l y t h a t t h e s e compounds have a psev.do-

o c t a h e d r a l arrangement o f s i x su lphu r sur rounding t h e

meta l .

The indium d i t h l o l e t e complexes knd t h e i r aZEucts

have c o o r d i n a t i o n numSers of f o u r , f i v e , and s i x . The

s t r u c t u r e of f o u r c o o r d i n a t i o n indiua(111) com?l.exes

~ ~ ( M X T ) ~ ] - and. [ I ~ ( T D T ) ~ ] - i s p o s s i b l y t e t m ' ? e d r a l , o r

d i s t o r t e d t d t r a h e d r a l , s i n c e t h e squa re -p l anm s t r u c t u r e

8 appea r s t o b e r e s t r i c t e d t o t h e diamagnet ic d c o ~ p l e x e s

s u c h as N i ( 1 1 ) , A u ( I I I ) , Rh(1) , e t c . , and a few

paramagnet ic square -p lanar Co(11) and ~ ~ ( 1 1 ) s p e c i e s . 83

The gomplexes [ I ~ ( ~ w A T ) ~ x ] ~ - - (X=Cl, B r and I ) I

a p p a r e n t l y have coo rd ina t ion nvnbers of f i v e w5ich

presumabl-y g i v e s e i t h e r a squ-are-pyramidal o r t r i g o n a l

bipyra-midal s t r u c t u r e . Following work on t h e s t r u c t u r e

of the cnrnpl exes [CO ( !VW) 2 ~ ~ h 3 ] - , [ ~ e (KBT) 2 ~ ~ h 3 ] - and

[ c ~ ( N K T ) ~ ~ ~ J - ; and r e c e n t work3* on t h e comnound InCl 2- 5 ( s e e diagram page 15 Figure-.II . ; l ) , it i s suggested that the

s t r u c t u r e of t h e s e compounds i s probably t e t r a g o n a l

pyramidal , s o t h a t t h e an ion [ I ~ ( ~ ? < . : M T ) - XI'- may have 2 -

t h e s t r u c t u r e shown i n F igu re V-13 .

F i g , V-13

Proposed s t r u c t u r e of F~(~PMT) XI- comp1.exes 2

X= C1, B r , and I.

A s tudy of t h e d e t a i l s o f t h e s t r u c t u r e of t h i s complex I

would be very valuabl-e. The s t r u c t u r e o f t h e s i x

c o o r 6 i n a t i o n compl-ex, [1n ( ~ Y K T ) - '-, is t e n t a t i v e l y

sugges t ed t o b e o c t a h e d r a l , f o l l owing Fackl-er 's work,

The complex [ I ~ ( ~ N T ) j3- h a s been s t u d i e d by x-ray 3

s i n g l e c r y s t a l method-se7, which h s s shown t h a t t h e Ins6

k e r n e l i n t h i s an ion h z s a d i s t o r t e d o c t a h e d r a l , s t r u c t u r e ,

w i th t h e In-S bond l e n g t h 2.598. The S-In-S a n g l e w i t h i n

t h e c h e l a t e r i n g is 80•‹ and t h e S-S d i s t a n c e i n t h e r i n g

3.39A. ( F i g u r e V-14).

Fig. V-14 The d i s t o r t e d oc tahedra l s t m c t u r e

The comgiexes [ ~ n ( l ~ ~ T ) ~ ~ h e n ] - , - [I~(ILNT)~~?~~]-, - t

[ ~ n ( ~ ~ j ~ ) ~ p h e n ] - , and ~ n ( T ~ ~ . ) ~ h i ~ ~ - may b e s i x c o o r ~ i n a t e ,

wi th d i s t o r t e d o c t a h e d r a l s t r u c t u r e . I t was emphasised

e a r l i e r t h a t t h e complex [ ~ n ( ~ l l ~ ) ~ ~ h e g - may have t h e c i s

and t r a n s i somer s , f o l l o w i n g t h e NKFi s t u d i e s .

CKAPTER VI I

SUGGESTIOX F09 FURTHER H E S E A X H -

The s t r u c t u r e o f snme [ I ~ ( E ~ N T ) ~ ] - , [I~(TDT) 2] -,

and [ I ~ ( ~ D " ! N T ) ~ x ] 2- compl.exes a r e worth s tudying by

x-ray crysta.1-lography, which w i l l shor.1 whether t h e

compounds have tetrahed.ra.1, o r d l s t o r t e d t e t r a h e d r a l

s t r u c t u r e s , and a l s o how s t r ~ n g i s t h e i n f l u e n c e of t h e

c h e l a t i n g s i n s system. Of s p e c i a l i n t e r e s t i s t h e

p o s s i b l y f i ve -coord ina t e bn( iXMT)2~]2- , - i n terms of t h e

a c t u a l geometry, and o f t h e bond I.engths 'In-X ( X = C ~ , B r

and I ) which should b e compared with knov~n s t r u c t u r e s ,

It would be very u s e f u l t o s tudy i n d e t a i l t h e

i n f r a r e d and Rarnan s p e c t r a of t h e complexes i n o r d e r t o

i d e n t i f y t h e In-S and In-N, In-0 s t r e t c h i n g modes

unambigu.ou.sly ,

Attempts t o i s o l a t e t h z d i f f e r e n t o x i d a t i o n s t a t e s

o f ~ ~ ( I . I N T ) ~ ] - , ~ ~ ( P ? R T ) ~ ] ~ - , LI~(TDT)~]-, [ I ~ ( ~ ~ < F T ) ~ x J ~ - , - [1n(!WT) 3]3- and t h e i r adduc ts , as p ~ s s i b l e In(0). I n ( 1 )

and 1n( 11) complex spec ies , , r e p r e s e n t s a' b i g chall-enge.

The s tudy of magnetic p r o p e r t i e s i n t h e d i f f e r e n t

o x i d a t l o n s t j t e s of t h e cornuound.~, pos s ib ly by ESR method,

would be very s i g n i f i c a n t .

During t h e p r e p a r a t i o n of 8-hydroxyquinolink a d d l c t s

wi th L I ~ ( ~ L I ~ T ) ~ ] - , i t yas found t h a t a compound wi th a n

indium con ten t of 16.7% vas i s o l a t e d . Th i s i s c l o s e t o

the composition of either E ~ ~ N [1n(i*$T~) 2 o x i ~ g (17 .Ol$)

or [I~(KNT) (oxine) 3] (16.64%). The IB spectrum hzs shsrm

the compound containins KNT ligand and the oxine, and

the XiYR spectrum has clearly shown the absence of the

+ cation EtbN . It may be of interest to study the

structure of such indium-oxine-dithiolate compl-exes in

more detail.

I

BIBLIOGRAPHY

(1) J. W. PIellor, ' " A Comprhznsive T r e a t i s e on Inorganic and

T h e o r e t i c a l Chemistry f t , Vol. V ,P.381-Lk05.

( 2 ) A. J. Car ty and D. G. Tuck, J, Chern. Soc., 6012 (1961,).

( 3 ) J;1. Klemn and H , K i l i a n , 2. Anorg. Chem., , 9 l d (1939).

( 4 ) A. J. Carty, S. J. P a t e l and D . . G . Tuck, Proceeding of 9 I n t e r a n t i o n a l Conference on Coordinat ion {?hem. (1966). P 36.

( 5 ) S. J. P a t e l and D. G. Tuck, J. Chem. Soc., ( A ) , 1870 (1968).

(6) D, G. Tuxk, E. J . Woodhouse and P. Carty, J . Chem. Soc., ( A ) , 1077 (1966).

( 7 ) D. G I Tuck, Coordinat ion Chemistry Reviews, (1) 286 (1966).

( 8 ) D , G. Tuck and E , J. 'C'Joodhouse, J. Chem. Soc., 6017 (1964).

(9) E1elvi.n E. ~ o b i n and P. Day, Advance i n Inorg . and Radio Chem. 10 ~ . 3 6 0 1 9 6 7 ) .

(10) D. M. Brow: and F. S. Dainton Trans. Faraday Soc., 62 , ;1139 (1966).

(11) 0. Hannebohn and -2. Rlernn, 2. Anorg. Chem. 22q, 337 (1936).

113) ,G. Wyrouboff, Bu l l . Soc. I4in., 30, 27$ (1907).

i l 4 ) P. L. Goggin, J . J. NcCollr and R. Shore, J. Chem. Soc. {.A) ; 1314. (1966).

( 1 5 ) 3 . J. P a t e l , D. B. Sowrby-and D. G . Tuck, I J. Cherfl, Sot* ( A ) ,131L: (1967).

(16) B . , 0. F i e l d and . C . J . Hardy, J. Chem. Soc. , ' 4J+2g (1964).

t

(17) B. F. G. 'Johnson and R. A . Walton, Inorg . Chem., 5 , 4-9 (1966).

(18) A. J . Carty a n d D. G. Tuck, J. Chem. Soc. ( A ) , 1081 (1966).

(19) B. 14. Ivanov and Y. T . Rabovic, Zhur Neorg. Khim. &, 2226 (1959).

(20) N. J. F r a s e r , fi. Gerrard and 3. A . Spi l lware , J . Inorg. Nucl. Chem. 26, 1k71.(19%l+).

(21) 1 . J. F r a s e r , If. ~ e r r a r d and R. Twaits, J. Inorg . 1Jucl. Chem. - 25, 637 (1964.).

( 2 2 ) S. J . P a t e l and D. G . Tuck, Unpublished r e s u l t s .

(23) G. W. A . Fowles, -il. A. H m d l e s s and 3.. A . Walton, .J. Inorg . Nucl. Chem. 3, 391 (1965).

(24) J. Celeda and D. G. Tuck, Unpublished r e s u l t s .

(25 j N. V.. Sidgwick, . .

1' The Chemical Elements and T h e i r Compounds 1t

C. U. P. ,1950, Vol. 1, P 476.

(26) J. B. Ekeley 2nd I!. A . P o t r a t z , J. Am. Chem. Soc., 2, 907 (1935).

( 2 7 ) T. IBoellor J. Am. Chem. Soc., 62, 21,!;.4 (191@).

(28) L.- A . Woodv~zrd and P. T. B i l l , .

J. Chem. Soc., 1699 (1955).

( 2 9 ) L. A . JSoodward and G. H . S i n g e r , J. Chem. Soc., 716 (19.58).

( 3 0 ) L. A . Woodwrd and 1.1. J. Taylor J . Chen. Soc., 41;.73 (1960 1.

(31) - i). G. Tuck and E. J . Tiocdhouse, Chem and I n d u s t q , 1363 (1964) .

(32) D. S. Brown F. W. B. ~ k n s t e i n and D. G. Tuck, Inorg. Chem., i n p r e s s .

( 3 3 ) G. .N. .Schrauzer and V . Fay-weg, J. Am. Chen.Soc.,.f&,:3221 (1962) ' .

(34) H. B. Gray, R William, T. Eerna l , and E. B i l l i g , J. Am. CheniScc., , 1,756. ($962) 6 . ,- . . e . - * - - . .

(35) H. 9. Gray, R. tJilliam, I c . ~ e S p ? l and E. E i l l i g , J. Am. Chem. Soc., &; 3596 (1962).

(36) E. B i l l i g , R. X i l l i a m I. Bernal and H. B. Gray, . .

Inorg . Chem., 2: 663 (1964.1 . ( 3 7 ) A Davison, M.. E d e l s t e i n , R. H. Holm and A . 3 . biqki,

Inorg . Chem., 2, 1227 (1963).

(38) A . Davison, N. E d e l s t e i n , R. H . Holm and A . H , Kaki, Inorg . Chem., 2, 814 (1961,-) .

( 3 9 ) H. B. Gray, fl T r a n s i t i o n Idetal Chemistry Vol. 1, P 239. Ed. R , L. C a r l i n , (1966).

(40) H. B. Gray, Coordina.tion Chemistry 'Eleviews, L, 156 (1966) .

(41) F. A . Cotton and G, Wilkinson, fl Advance I n o r g s n i c Chemistry 2nd Sd. (1966).

(42) I?. B. King, Inorg . Chem., 2, 641 (1963).

(43) R. E. D. Clark, Analys t , - 61, 2.42 (i936!. .

(l+i$) R. E. D. Clark , Analys t , 62, 661 (1937).

(45) T. W. G i l b e r t ~ r . and E. B. S a n d e l l , J. Am, Chem. Soc., 62, 332 (1960).

(4.6) R. E isenber , E. I. S t i e f e l , B. C. Rosenber andz. B. Gray, J . Am. Chem. Soc., E%, 2G74 (1966).

( 6 2 ) I. 1.1. Kolthoff . and I. L. Lingane, Chem. Review, &, 1-94 (1939)o

(63) E. bl. Hattox and DeVries, 1 J. .Am. Chem. Soc. , , 2126 (1936).

( 3 4 ) S. Bokornori, J. Am. Chem. Soc, , 42, 2373 (1933).

( 6 5 ) J. Heyrovsky, C. R , .Acad. S c i . , 179, 1261+ (192b).

(66) D. V. Cozzi, 2. Electrochem., - 57, 407 (1953).

(67) J. A , Schuf le , ili. F. Stubbs a n d 3 . E. Xitmzn, J . Am. Chem Soc., 73, 1013 (1951).

( 6 8 ) L. Ideites and T. i . iei tes, Anal. Chem., 20, 984 (194.8).

(69) A. 5. Vlcek, " Progress i n Inorgan ic Chemistry Vol. 5,P211-379, Ed. F. A. Cot ton, I n t e r s c i n c e (1962).

(70) G. N. Schrauzer , t f T r a n s i t i o n Metal Chemistry l1 Vol, l k P 299, Ed. R. L. C a r l i n , Ibiarcel 3ekker (19681.

(71) A. Davison, I{. E d e l s t i e n , R. H. Ilolmand A , E. Xaki, J. Am. ' Chem. Soc., ;6, 2799 (1964.).

(72) E. L . E l l i e l , ' 1 Stereochemis t ry of Carbon Compounds If

NcCrav,GHill (1962) . (73) J. E. Fergusson and R. S , Nyholm,

I n t e r n a t i o n a l Conf. on 1962 No. 62.

( 7 4 ) 3. A. McCleverty, J. Looke and E. J. 'vharton, J . Chem. Soc . , (A) , 1293 (196G).

(75.) G. N. Schruezer and Y. P. Maywe 8 J . Am. Chem. Soc.,8'J, 3 5 3 (19651..

(76) D. 14. Adam and J. B, .Cornel l J. Chei;~. SOC. ( A ) , 884 1196'7).

(77) J. P. F a c b l e r Jr . and D: Coucou Vanis? ' I J . Am. Chern. Soc., €%, 3913 (1906).

I' . (78) L. J. Bellamy,

fl Advance i n I n f r a r e d Group Frequencies " lblethuen and Cob (1968) . P Zl:.-25.

(79) D. 2.1. Adarns, A . J . Car ty , P a Car ty and 3 . G. Tuck, J . Chem. Soc. ( A ) , 162 (1966) .

($3) ,I$.- Ii$. Greenwood, D . J . Pr ince and B. D. Straugham, J . Chem. Soc. ( A ) , 1694 (1968).

(81) I<, Tio, 2'. l sobe and K. Sone, J, C h m . Phy., 2, g61 (1959).

( 8 2 ) 1.:. F. A . Dove and J. G . H ~ l l l e t t , i n p r e s s ,

(83) S. I . Shupack, E. Eillig and 11. B. Gray J. A$. Chen. Soc., 86, 4594 (1961)).

--, . ( ~ 4 ) R. m s e n b e r g , Z. Dori , H . B e Gray and J, A . I b e r s , I n o r g , Cherg., z,. 71:.1 (1968).

( 8 5 ) C. H. Lansford, E. B i l l i g , S ? I. Shupack and. H . E . Gray, J. Am. Chem. Soc., 86, 2985 ( 1964.).

(861 *W. C , Hamilton and I. Bern21 Inorg . Chem., 6 , 2903 f1967) .

(87) F a i,!, B. E i n s t i e n , G. Pun te r , D. G. Tuck and ;.I. K. Y a ~ g , 1 I Chem, Com:i. ,&22 (1968) .

L.

-134-

LIST OF - ABBREVIATIONS i

bipy = 2,2'-bipyxidyl

dma = N,N1-dimethylacetamide

- DME = dropping mercury electrode

dmf = dimethylformamid'e . dmso = dimethylsulphoxide

en = ethylenediamine

o x h e = 8-hydroxyquinoline

iMNT = 1 ,l '-dicyanoethylenp2,2'-dithiolate - L = ligand

= molar conductivity

MKT = maleoni triledi thiolate Ox. = Oxidation

phen = 1,lO-phenanthroline

5-nitro-o-phen = 5-nitro-1 ,lo-phenanthroline

PY

Pic Red

TDT

s o h

X

s

m W

sh

CPS

= pyridine

= picoline

= reduction

= solution

= halides

= strong 1 = medium } in infrared spectra

= weak = shoulder . - 1 == cycles per second